The Journal of Raptor Research Is Distributed Quarterly to All Current Members

: : .

THE RAPTOR RESEARCH FOUNDATION, INC. (Founded 1966) http://biology.boisestate.edu/raptor/

OFFICERS

PRESIDENT: Brian A. Millsap SECRETARY: Judith Hfnckel VICE-PRESIDENT: David M. Bird TREASURER: Jim Fitzpatrick

BOARD OF DIRECTORS

NORTH AMERICAN DIRECTOR #I INTERNATIONA!. DIRECTOR #3:

Steve Hoffman S i eve Re.dpath NORTH AMERICAN DIRECTOR #2: DIRECTOR AT LARGE #1: Jemima ParryJones Gary Santolo DIRECTOR AT LARGE #2: Eduardo Inigo-Elias

NORTH AMERICAN DIRECTOR #.3: DIRECTOR AT LARGE #3: Michael W. Collopy Ted Swem DIRECTOR AT I.ARGE #4: Carol McIntyre INTERNATIONAL DIRECTOR #I DIRECTOR AT LARGE #5: John A. Smallwood Nick Mooney DIRECTOR AT LARGE #6: Daniel E. Varland INTERNATIONAL DIRECTOR #2: Ruth Tingay

EDITORIAl. STAFF

EDITOR: James C. Bednarz, Department of Biological Sciences, P.O. Box 599, Arkansas State University, State University, AR 72467 U.S A.

ASSISTANT EDITOR: Jennifer L. Norris

ASSOCIATE EDITORS James R. Beltiioff Joan L. Morrison Clint W. Boat Fabrizio Sergio Cheryl R. Dyksfra Ian G. Warkentin Michaei. L Goldstein James W. Watson

BOOK REVIEW EDITOR: Jeffrey S. Marks, Montana Cooperative Research Unit, University of Montana, Missoula, MT 59812 U.S.A. SPANISH EDITORS: Carlos Daniel Cadena, Lucio R. Malizia, Cintia Cornelius EDITORIAI. ASSISTANT: Joan Clark

The Journal of Raptor Research is distributed quarterly to all current members. Original manuscripts dealing with the biology and conservation of diurnal and nocturnal birds of prey are welcomed from throughout the world, but must be written in English. Submissions can be in the form of research articles, short communications, letters to the editor, and book reviews. Contributors should submit a typewritten original and three copies to the Editor. All submissions must be typewritten and double-spaced on one side of 216 X 278 mm ( 8V2 X 11 in.) or standard international, white, bond paper, with 25 mm (1 in.) mar- gins. The cover page should contain a title, the author’s full narae(s) and address (es). Name and address should be centered on the cover page. If the current address is different, indicate this via a footnote. A short version of the title, not exceeding 35 characters, should be provided for a running head. An abstract of about 250 words should accompany all research articles on a separate page. Tables, one to a page, should be double-spaced throughout and be assigned consecutive Arabic numerals. Collect all figure legends on a separate page. Each illustration should be centered on a single page and be no smaller than final size and no larger than twice final size. The name of the author(s) and figure number, assigned consecutively using Arabic numerals, should be pencilled on the back of each figure. Names for birds should follow the A.O.U. Checklist of North American Birds (7th ed., 1998) or another authoritative source for other regions. Subspecific identification should be cited only when pertinent to the material presented. Metric units should be used for all measurements. Use the 24-hour clock (e.g.,

0830 H and 2030 H) and “continental” dating (e.g., 1 January 1999). Refer to a recent issue of the journal for details in format. Explicit instructions and publication policy are outlined in “Information for contributors,”/. Raptor Res., Vol. 38(4), and are available from the editor.

Submit manuscripts to J. Bednarz at the address listed above.

COVER: “Vigilance” painting by Robert Bateman of Bald Eagle {Haliaeetus leucocephalus) ^Robert Bateman. Reproduction rights courtesy of Robert M. Bateman, Boshkung, Inc. (www.robertbateman.ca) Contents The Influence of Tide and Weather on Provisioning Rates of Chick-rearing

Bald Eagles in Vancouver Island, British Columbia. Kyle Hamish Elliott,

Christopher E. Gill, and John E. Elliott 1

First Complete Migration Cycles for Juvenile Bald Eagles {Haliaeetus

LeUCOCEPHALUS) from Labrador. Dawn K. Laing, David M. Bird, and Tony E. Chubbs 11

Investigating Fall Movements of Hatch-year Flammulated Owls ( Otus FLAMMEOLUS) IN CENTRAL NeW MEXICO USING STABLE HYDROGEN ISOTOPES.

John P. DeLong, Timothy D. Meehan, and Ruth B. Smith 19

Effects of Breeding Experience on Nest-site Choice and the Reproductive

Performance of Tawny Owls {Strix aluco) . Lajos Sasvari and Zoitan Hegyi 26

The Status of Diurnal Birds of Prey in Turkey. Levent Turan 36 Short Communications

Seasonal Diet of the Aplomado Falcon {Falco femoraus) in an Agricultural Area of Araucania, Southern Chile. Ricardo A. Figueroa Rojas and Ema Soraya Corales Stappung 55

Mesostigmatic Mites (Acari: Mesostigmata) in White-tailed Sea Eagle Nests {Hauaeetus albicilul) . DariuszJ. Gwiazdowicz, Jerzy Bloszyk, Tadeusz Mizera, and Piotr Tryjanowski 60

Vertebrate Prey of the Barn Owl ( Trro alba) in Subtropical Wetlands of Northeastern

Argentina AND Eastern Paraguay. Ulyses F.J. Pardinas, Pablo Teta, and Sofia Heinonen Fortabat 65

Absence of the Eurasian Griffon (Gypsfulvus) in Northern Morocco. Jose Rafael Garrido, Alvaro Camiha, Mariangela Guinda, Maria Egea, Nourdine Mouati, Alfonso Godino, and

J.L. Paz de la Rocha * 70

Artificial Nest Structure Use and Reproductive Success of Barn Owls in Northeastern Arkansas. Paul M. Radley and James C. Bednarz 74

Abundance and Diet of Alexander’s Kestrel {Falco tinnvnculus alexandri) on Boavista Island

(Archipelago of Cape Verde) . Diego Ontiveros 80

The Role of Thyroxine on the Production of Plumage in the American

Kestrel {Falco sparverius). Michael J. Quinn, Jr., John B. French, Jr., F.M. Anne McNabb, and Mary Ann Ottinger 84

Observations of Nesting Gray-headed Kites {Leptodon cayanensis) in Southeastern Brazil. Eduardo Pio Mendes de Carvalho Filho, Gustavo Diniz Mendes de Carvalho, and Carlos Eduardo Alencar Carvalho 89

Cooperative Nesting by a Trio of Booted Eagles {Hieraaetus pennatus). Jose E. Martinez,

Carlos Gonzalez, and Jose F. Calvo 92

Timing and Abundance of Migrant Raptors on Bonaire, Netheriands Antilles. Vincent Nijman, Tineke G. Prins, andJ.H. (Hans) Reuter 94

The Relationship of Foraging Habitat to the Diet of Barn Owls {Tyto alba) from Central Chile. Sabine Begall 97 Letters

Iverson (2004) on Spotted Owls and Barred Owls: Comments on Methods and Conclusion. Kent B. Livezey 102

Using a Portable, Anchor-bolt Ladder to Access Rock-nesting Osprey. Tony E. Chubbs,

Matthew J. Solensky, Dawn K Laing, David M. Bird, and Geoff Goodyear 103

Attempted Predation on a Large-tailed Nightjar ( Caprimulgus macrurus) by an Eastern Marsh-Harrier {Circus spilonotus) in Coastai. Vietnam. James A. Fitzsimons 106

Red-tailed Hawk Depredates Mississippi Kite Nestling at Dawn. Karl E. Miller 108

First Nesting of Cooper’s Hawks {Accipiter cooperii) in New York City Since 1955. Robert DeCandido 109 Manuscript Referees 110

provided by Arkansas State University to assist in the publication of the journal. ——

THE JOURNAL OF RAPTOR RESEARCH

A QUARTERLY PUBLICATION OF THE RAPTOR RESEARCH FOUNDATION, INC.

VoL. 39 March 2005 No. 1

THE INFLUENCE OF TIDE AND WEATHER ON PROVISIONING RATES OF CHICK-REARING BALD EAGLES IN VANCOUVER ISLAND, BRITISH COLUMBIA

Kyle Hamish Elliott Canadian Wildlife Service, 5421 Robertson Road, Delta, British Columbia V4K 3N2 Canada

Christopher E. Gill Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6 Canada

John E. Elliott ^ Canadian Wildlife Service, 5421 Robertson Road, Delta, British Columbia V4K 3N2 Canada

Abstract. We investigated how tide and weather (temperature and rainfall) influenced Bald Eagle {Haliaeetus leucocephalus) provisioning rates on the east and west coasts of Vancouver Island, British Columbia during the 1996 breeding season. Eagles nesting on the west coast had less frequent prey- delivery rates (3.2 ± 1.0 deliveries/d, N = 6 nests) than those nesting on the east coast (7.2 ± 2.8 deliveries/d, N ~ 7 nests). Prey-delivery rates were negatively correlated with precipitation on the west coast, but not on the east coast. On both coasts, prey-delivery rates were negatively related with temperature (r = —0.45), as nestlings have lower energetic needs during warm weather, and positively related with adult attendance (r = 0.35). Prey-delivery rates were highest at intermediate tide height and early in the day, reflecting food availability. Intertidal fish were a major component of eagle diet on the east coast (plainfin midshipman [Porichthys notatus] = 46% by frequency) while pelagic fish were the major component on the west coast (Pacific mackerel [Scomber japonicus] = 92%). We concluded that landscape features (e.g., tidal flats) and weather (e.g., rain and temperature) interact to influence provisioning rates of Bald Eagles on Vancouver Island, and that these factors may drive spatial variation in eagle productivity.

Key Words: Bald Eagle, Haliaeetus leucocephalus; British Columbia, productivity, weather, tides.

LA INELUENCIA DE lA MAREA Y EL CLIMA EN LAS TASAS DE APROVISIONAMIENTO DE HAL- IAEETUS LEUCOCEPHALUS QfJE SE ENCONTRABAN CRIANDO EN VANCOUVER ISLAND, BRITISH COLUMBIA

Resumen. Investigamos como la marea y el clima (temperatura y precipitaciones) influenciaron las tasas de aprovisionamiento por parte de individuos de Haliaeetus leucocephalus en las costas este y oeste de Vancouver Island, British Columbia, durante la estacion reproductiva de 1996. Las aguilas que estaban nidificando en la costa oeste presentaron tasas de entrega de presas menos frecuentes (3.2 ±1.0 entregas/d, N = 6 nidos) que aquellas que estaban nidificando en la costa este (7.2 ± 2.8 entregas/d,

N = 7 nidos) . Las tasas de entrega de presas estuvieron negativamente correlacionadas con la precipitacion en la costa oeste, pero no en la costa este. En ambas costas, las tasas de entrega de presas estuvieron relacionadas negativamente con la temperatura (r = —0.45), debido a que los pichones

^ Email address: [email protected]

1 2 Elliott et al. VoL. 39, No. 1

tienen necesidades energeticas menores durante periodos calidos, y relacionadas positivamente con la presencia de los adultos (r = 0.35). Las tasas de entrega de las presas fueron mas altas a niveles inter- medios de altura de la marea y al comienzo del dia, reflejando la disponibilidad de alimentos. Los peces de la zona intermareal constituyeron un componente importante de la dieta de las aguilas en la costa este {Porychthys notatus = 46% por frecuencia), mientras que los peces pelagicos constituyeron el componente mas importante en la costa oeste (Scomberjaponicus = 92%). Concluimos que las caracteristicas del paisaje (e.g., pianos mareales) y el clima (e.g., Iluvia y temperatura) interactuan para influenciar las tasas de aprovisionamiento en H. leucocephalus en Vancouver Island, y que estos factores podrian con- ducir a variaciones espaciales en la productividad de las aguilas. [Traduccion del equipo editorial]

Food availability is a key factor regulating raptor (Newton 1978, 1998, Kruger and Lindstrom 2001, productivity in natural ecosystems (Newton 1979, McDonald et al. 2004). For example, rain reduced 1998), including Bald Eagles (Haliaeetus leucoce- the ability of Ospreys to locate prey by increasing phalus-, Hansen 1987, Dykstra et al. 1998), White- the number of ripples on the water surface (Grubb tailed Sea Eagles {Haliaeetus albicilla; Helander 1977). In addition, the number of rainy days dur- 1985), African Fish-Eagles {Haliaeetus vocifer, Harp- ing early spring was negatively correlated with Bald er et al. 2002), Wedge-tailed Eagles {Aquila audaxr, Eagle productivity in southeastern Alaska (Gende Ridpath and Brooker 1986), Golden Eagles {Aquila et al. 1997), but not in the drier interior regions chrysaetos; Watson et al. 1992), and Ospreys {Pan- of Alaska (Steidl et al. 1997). dton haliaetus] van Daele and van Daele 1982), In this study, we investigated the factors influ- among others (Platt 1976, Dykstra et al. 2003, Hak- encing provisioning rates at Bald Eagle nests along karainen et al. 2003). Although some Bald Eagle the Vancouver Island shoreline in coastal British populations are still at least partly influenced by Columbia. Elliott et al. (1998) and Gill and Elliott toxic contamination (Anthony et al. 1993, 1994, (2003) showed that eagles nesting on the west 1999, Kumar et al. 2002, Bowerman et al. 2003, coast had lower productivity than those nesting on

Dominguez et al. 2003), several populations now the east coast, and conjectured that this was due appear to be regulated by natural agents, primarily to wetter springs and fewer tidal flats limiting the food abundance (e.g., Dzus and Gerrard 1993, amount of food brought to nests. We therefore hy-

Donaldson et al. 1999, Anthony 2001, Stout and pothesized that (1) provisioning rates would be Trust 2002, Gill and Elliott 2003). negatively correlated with tide height and (2) pro- Landscape features, especially tidal flats, influ- visioning rates would be lower during periods of ence eagle-prey availability, and therefore, produc- rain. tivity (Hansen 1987, Watson et al. 1991, Dzus and Previous investigators (Gerrard et al. 1979, Bor-

Gerrard 1993, Gende et al. 1997, Wilson and Arm- tolotti 1984a, Jenkins 1989, Kennedy and Mc- strong 1998, Watson 2002). Weather also influenc- Taggart-Cowan 1998, Warnke et al. 2002) have de- es raptor reproductive success, either by affecting scribed Bald Eagle nesting behavior using direct adult or chick energetic needs (Newton 1978, observation and time-lapse photography. Warnke 1998, Stalmaster and Gessaman 1984), prey avail- et al. (2002) established several benchmarks for ability (Seavy et al. 1998, Panasci and Whitacre the nest provisioning and chick behavior of an in-

2000, Harper et al. 2002, Jaksic et al. 1997), or land population that did not seem to be limited by adult foraging effectiveness (Grubb 1977, Newton food. In this paper, we used both methods to com- 1978, Stinson 1980, Gilchrist and Gaston 1997, pare the behavior of eagles from coastal Vancouver

Gilchrist et al. 1998, Fritz 1998). Whereas rainfall Island with those presented by Warnke et al. usually increases foraging success for tropical rap- (2002) for Wisconsin. tors, due to increased productivity at lower trophic Study Area and Methods levels during the rainy season and decreased heat stress in canopy nesters (Seavy et al. 1998, Panasci Study Area. During May-July 1996, we monitored Bald Eagle nests on the east (Crofton, 48.9°N, 123.7°W) and and Whitacre 2000, Harper et al. 2002, Jaksic et al. west (Barkley Sound, 48.9°N, 125. 3°W) coast of southern 1997, Touchton et al. 2002), rainfall usually reduc- Vancouver Island, British Columbia. On the west coast, es prey availability, increases chick energetic needs, the marine environment drops off steeply from shore adult-nest attendance in temperate regions while the sheltered waters the east coast include large and . on March 2005 Bald Eagle Provisioning Rates 3

tidal flats where many eagles forage. In addition, the ex- regression to examine the effects of adult nest atten- posed west coast tends to be cooler and windier, with dance (percent of each day when at least one adult was events, the protected east coast, and present, averaged over each week) mean daily tempera- more storm than , nesting begins ca. 1 mo later (Elliott et al. 1998). Within ture, and chick age (independent variables) on mean each study area, we selected nests where placement of daily prey and energy deliveries, averaged over each week video recording equipment afforded a good vantage for (dependent variables). Within this multiple linear re- nesting observations. gression, we used ANCOVAs to compare prey deliveries Observations. We positioned six (three on each coast) on days with and without rain on each coast and to com- miniature CCD cameras (V-1205, Sony, Vancouver, BC, pare prey deliveries relative to temperature on each Canada) 2 m above the nests when nestlings were ca. 4 coast. In addition, we employed multiple linear regres- wk old. Our observations corresponded ca, to the “mid- sion, using a quadratic model, to examine the effect of dle nesting stage” identified by Warnke et al. (2002). tide height, time of day, and prey deliveries (hourly Cameras were housed in waterproof compartments, cam- mean) between coasts. Prior to using parametric statis- ouflaged using paint and vegetation and connected via tics, we tested for homogeneity of variance (Levene’s power and RG-8UM video lines (RG-8UM, CB World, test) and normality (Kolmogorov-Smirnov) . Bonferroni Lansing, MI U.S.A.) to a DC VCR (Panasonic AG-1070 adjustments were completed on multiple comparisons one frame- s ^ Secaucus, NJ U.S.A.) on the ground. We We considered results to be significant if P < 0.05. The replaced the videotapes every 3 d. VCRs were housed in values reported are means ± SD. waterproof compartments 20 m from the nest tree and programmed to record from 0500-1100 H and 1430- Results 2030 H (812 hr total footage). Two 12-volt deep-cycle- marine batteries in protective housing supplied power. All nestlings present at the beginning of the We analyzed video recordings by viewing on a television study period survived to the end of the study pe- monitor. riod, with more young produced at the sampled We conducted direct observations using 20-60 X spot- nests on the east coast (2 young per occupied nest) ting scopes from a blind at four nests on the east coast than on the west coast {x — 1.2) of Vancouver Is- and three on the west coast (^6 d/nest, each 16 continuous hours dawn to dusk) for 1344 hr total. Nestlings land (Table 1). were 2-10 wk old. Observers worked in pairs 100-300 m Factors Influencing Provisioning Rates. Prey-de- from the nest, with individual observers switching every livery rates varied significantly between coasts. The 2 hr (Warnke et al. 2002). west coast had fewer prey deliveries (? = 2.3, df = To corroborate the compatibility of observation meth- S, P= 0.008) per day and lower mean prey biomass ods, we collected direct observation and video data si- = multaneously for 20 hr. As was found by Dykstra et al. (^ — 1.9, df = 8, P 0.04) than the east coast (1998) and Warnke et al. (2002), both methods had (Table 1). However, there was no difference (t — compatibility agreement) for determining good (>98% 2.2, df = 10, P = 0.43) in the mean daily energy the number of prey deliveries, prey species delivered, and delivered (Table 1). There was also no difference chick and adult behavior. We consequently pooled both in the prey-size distributions {t = 0.73, df = data sets. 3, P We recorded adult nest attendance, number and type = 0.25) for Pacific herring (Clupea harengus), the (class and species when possible) of prey delivered, and only species for which there was significant overlap eaglet behavior (standing, feeding, preening, fighting between the two coasts (Table 2). A multiple linear with siblings, exercising wings, playing with nest material, regression (P^ ^ fl.22, P = 2.61, df - 2103, P = and walking around the nest; Warnke et al. 2002). All behaviors except “standing” were considered “active.” 0.07) indicated no correlation between nestling We classified prey items into four length categories (7- age and the number of prey deliveries {t = 1.34, 15 cm, 15-23 cm, 23-30 cm, 30-40 cm) using the prey df = 202, P = 0.66). However, there was a peak in item’s size relative to adult bill or toe-pad length. Prey prey deliveries at about 4 wk, corresponding to the length and species was then used to estimate biomass period of maximum growth (Warnke et al. 2002). using equations and experimental values from the literature as described by Dykstra et al. (1998) and Gill and Using this regression we found a negative relation- Elliott (2003). Our analyses focused on the relationships ship between mean daily temperature and number variables deliveries (rather between and prey than energy of prey deliveries (t = —2.35, df = 202, P = 0.02), delivered) as prey-delivery rates were estimated with and the mean number of prey deliveries and the greater certainty. Environment Canada weather stations presence of rain the west coast {t — —3.6, df = at Ucluelet (west coast) and Crofton (east coast) provid- on ed weather data. 103, P < 0.001), but not on the east coast {t — Statistical Analyses. Statistical analyses were performed 0.65, df = 98, P = 0.54). In addition, prey-delivery using Data for individual nests were pooled STATISTICA. rates at both coasts were strongly influenced by the on each coast if an analysis of covariance (ANCOVA) time of day (Fig. 1). On both coasts, there was a gave no significant difference among nests. We pooled the data for both coasts if the interaction term (coast X significant quadratic relationship between tide variable) was not significant. We used a multiple linear height and prey-delivery rates (Fig. 2), with the 4 Elliott et al. VoL. 39, No. 1

Table 1. Provisioning rates to Vancouver Island Bald Eagle nests during 1996. Values indicated are daily means (SD) averaged over the entire nestling period.

Energy Delivered

Nest ID No. Nestlings Observations Prey-Delivery Rate per Nestling (kj) Prey Biomass (g)

CN-Br^ 2 6 7.7 (3.5) 1517 (345) 630 (87) CN-Ch^ 2 6 10.8 (3.4) 3681 (780) 955 (199) CN-Mo^ 2 6 9.0 (4.1) 3210 (2008) 821 (523) CN-WN*’ 2 14 9.6 (6.6) 872 (692) 209 (136) CN-WS^ 3 12 4.5 (2.2) 1490 (990) 380 (367) CS-MB*’ 2 11 5.0 (3.5) 1539 (794) 417 (212)

CS-PM^’ 1 11 3.6 (2.3) 1448 (539) 373 (135) Mean, east 2.0 7.2 (2.8) 1965 (1046) 541 (270) BS-AP I 12 2.3 (1.1) 2314 (777) 345 (101) BS-Ch" I 6 4.8 (3.2) 3547 (1060) 510 (151) BS-Nu^ 2 6 4.0 (1.9) 1691 (1124) 236 (158) BS-Ri=^ 1 5 2.6 (1.1) 2584 (834) 365 (111) BS-SB'^ 1 13 2.9 (1.4) 1811 (548) 295 (81) BS-Sp’’ 1 11 2.8 (1.5) 2201 (674) 330 (94) Mean, west 1.2 3.2 (1.0) 2358 (669) 347 (92) Mean, pooled 1.6 5.4 (2.9) 2147 (880) 451 (224)

® Video cameras. Direct observations.

greatest prey-delivery rates at intermediate tide common prey item was plainfin midshipman (Po- heights. Therefore, we reject the hypothesis that rychthys notatus) while on the west coast it was Pa- provisioning rates were negatively related to tide cific mackerel {Scomber japonicus). At both loca- height, at either coasts, and accept the hypothesis tions, Pacific herring {Clupea harengus) was the that provisioning rates were negatively correlated second most common prey item. Direct observa- with rain only on the west coast. tions tend to overrepresent easily identified, com- Adult and Nestling Behavior. On both coasts, mon species so that actual percentages for major adult nest attendance was positively correlated with prey items may be exaggerated (Mersmann et al. brood size (r = 0.33, P < 0.01) and mean number 1992, Dykstra et al. 1998). of prey deliveries per hour per eaglet (r = 0.34, P Discussion < Fig. negatively correlated with ea- 0.002; 3) , and glet age (r = 0.27, P < 0.01). Mean daily eaglet Bald Eagle provisioning rates were clearly influ- activity levels were higher on the west coast (42 ± enced by time of day, tide, and weather. High pro- 5% of the day) than east coast (27 ± 3%) of Van- visioning rates tended to be at intermediate tide couver Island. Eaglets on the west coast spent more heights, at low temperatures, during rainless peri- time standing, feeding, preening, fighting with sib- ods, and early during the day. The decline in pro- lings, exercising wings, playing with nest material, visioning rate with time of day likely reflects both and walking around the nest than their counter- nestling satiation and declining prey activity, as parts on the east coast. On both coasts, eaglet Watson et al. (1991) reported in the Columbia Riv- mean daily activity was independent of hatching er estuary. order (P > 0.6), negatively correlated with adult The mean prey-delivery rate for Vancouver Is- nest attendance (r — 0.46, P < 0.001) and positive- land eagles (5.4 prey/d) was remarkably similar to ly correlated with eaglet age (r = 0.34, P < 0.005; the benchmark of 5.2 prey/d reported by Warnke Fig. 4). et al. (2002), which they considered to indicate ad- Prey Type. There was considerable variation in equate prey availability to support high Bald Eagle prey type between the east and west coasts. Fish reproductive success. Our data support this bench- made up the majority of the diet at both locations mark, as territories on the east coast had consis- (Table 2). However, on the east coast the most tently high productivity, while those on the west )

March 2005 Bald Eagle Provisioning Rates 5

Table 2. Prey delivered to Vancouver Island Bald Eagle nests in 1996.

Prey Type Percent of Diet^ No. OF Deliveries Energetic Value (kj)^

East Coast

Fish 85.1 215 438

Plainfin midshipman {Parichthys notatus) 43.0 65 403 Pacific Herring {Clupea harengus) 10.0 23 265

Coho Salmon ( Oncorhynchus kisutch) 10.9 2 3304 Pollock (Theragra chalcogramma) 5.0 1 3075 Flounder (Bothidae/Pleuronectidae spp.) 1.7 2 526 Ling cod (Ophiodon elongates) 1.7 3 349

Surf Perch {Hyperprosopon ellipticum) 0.6 1 352

Bird 4.0 2 2220

Mallard duckling {Anas platyrhynchos) 1.7 1 1046

Pigeon Guillemot {Cepphus columha) 5.6 1 3394

Mammal 10.9 4 3029

European rabbit ( Sylvilagus spp. 19.6 2 5967 Rodent (Rodentia spp.) 0.1 1 90

West Coast Fish 94.7 85 963

Pacific Mackerel {Scomber japonicus) 90.8 37 1713 Pacific Herring {Clupea harengus) 6.2 14 307

Coho Salmon ( Oncorhynchus kisutch) 1.9 1 1343 Flounder (Bothidae/Pleuronectidae spp.) 1.0 2 334 Sculpin (Cottidae spp.) 0.1 1 88

Shiner Perch ( Cymatogaster aggregate) 0.1 1 37 Surf Perch {Hyperprosopon ellipticum) 0.0 1 15

Bird 6.5 1 4555

Mallard duckling {Anas platyrhynchos) 1.2 1 1046

* By energy. Averaged over all deliveries.

Figure 2. Quadratic regression of provisioning rates for east Bald Eagles on the ( ) and west () coasts of Van- Figure 1. Linear regression of mean number of prey couver Island during 1996 relative to tide height (east: deliveries per hour relative to time of day at Vancouver prey deliveries = —0.75 X [tide height]^ + 0.25 X [tide Island Bald Eagle nests in 1996 (prey deliveries = —0.033 height] — 0.016, = 0.69; west: prey deliveries = —0.052

[time of day] + 0.0458; -fi = 0.50). Data were pooled for X [tide height]^ + 0.16 X [tide height] + 0.02V; = east and west coasts. 0 . 68 ). . .

6 Elliott et al. VoL. 39, No. 1

Figure 3. Vancouver Island Bald Eagle adult nest atten- Figure 4. Bald Eagle nestling activity percent dance (percent of total observation time when adult was Mean (A— at nest) relative to prey-delivery rate (prey deliveries per of total observation time when nestling was active) and chick per hr). Each data point represents one nest, av- adult attendance (I—percent of total observation time eraged over the 1996 season (prey deliveries = 0.0016 when adult was present) relative to nestling age (nestling = — = = [adult nest attendance] + 0.22; = 0.12). activity 6.1 X age 3.5; 0.92; adult attendance — 11.3 X age + 97; = 0.87). Nests {N = 13) were studied on Vancouver Island in 1996. coast, a region with consistently low productivity, were below this benchmark. Despite the difference availability can affect spatial variation in productiv- in number of prey items and biomass delivered, ity. The east-coast population, which consistently the total energy delivered per chick was higher on produced more young than needed to replace in- the west coast than the east coast, although the dividuals lost to mortality (Elliott et al. 1998), had mean total energy delivered to the nest was similar, higher prey-delivery rates than the west-coast pop- as east coast nests averaged more chicks. Nestlings ulation, which did not produce enough young to on the west coast met the field energetic require- compensate for mortality (Elliott et al. 1998) ments of 2427 ±100 kj/d for nestlings in northern The relationship between tide height and pro-

Wisconsin (Dykstra et al. 2001a), while those on visioning rates highlights the importance of tidal the east coast did not. Nestlings may have experi- flats for nesting eagles. The influence of tide on enced higher energetic demands on the west coast Bald Eagle foraging habits has been documented due to substantially cooler conditions more similar in Alaska (Ofelt 1975, Wilson and Armstrong to Wisconsin. Eagles on the west coast foraged pri- 1998), British Columbia (Hancock 1964, Elliott et marily on Pacific mackerel, a high-energy species al. 2003), and Washington (Watson et al. 1991, (1713 kj; Ann 1973) that was unusually abundant Garrett et al. 1993), and appears to be character- due to surface water warming in the late 1990s istic of coastal populations in the Pacific North- (Gill and Elliott 2003). Thus, eagles on the west west. The peak in prey deliveries at intermediate coast seem to make up for the low quantity of prey tide heights is likely because the plainfin-midship- delivered by increasing prey quality (Wright et al. man-breeding zone is exposed at this tide level (El-

1998, Hilton et al. 1998), as has been known to liott et al. 2003); in the Columbia River estuary, occur in other raptors (Barton and Houston 1993) where eagles forage primarily on fish that are most Many studies have shown a strong relationship easily captured in shallow water, foraging success between food abundance and reproductive success peaks at low tide (Watson et al. 1991). m raptors. For example, reproductive success in Weather also influenced provisioning rates. The many temperate and arctic raptors closely follows decline in provisioning rates with temperature changes in small mammal populations (e.g., Mc- likely reflects lower chick-energy demands during

Invaille and Keith 1974, Smith et al. 1981, Korpi- warm weather, while the lower provisioning rates maki 1992, Wiehn and Korpimaki 1997), while fish on rainy days may reflect reduced adult foraging abundance influences productivity in piscivores efficiency due to altered visibility (Grubb 1977) or such as Ospreys (van Daele and van Daele 1982), prey behavior (Newton 1978). Furthermore, rain White-tailed Sea Eagles (Helander 1985), African increases eagle energetic requirements by up to Fish-Eagles (Harper et al. 2002), and Bald Eagles 21% (Stalmaster and Gessaman 1984), and adults (Hansen 1987, Dzus and Gerrard 1993). Our re- may need to eat more during rainy days, leaving sults demonstrate one mechanism by which prey less prey for them to deliver to their nestlings. The ) .

March 2005 Bald Eagle Provisioning Rates 7

larger impact of rainfall on the outer coast on prey- study was fish (Table 2), outlining the importance delivery rates supports the conjecture that low pro- of using direct observations, as analysis of prey re- ductivity on the outer coast is partially attributable mains at nests often leads to the underestimation to harsh and unpredictable weather (Gende et al. of fish prey (Todd et al. 1982, Mersmann et al. 1997, Elliott et al. 1998). Storms impact the repro- 1992). For comparison, the proportion of fish in ductive success of other raptors. For example, win- diets of eagles nesting in coastal regions varied ter severity delays reproduction and reduces pro- from 42% in Louisiana (Dugoni et al. 1986) to ductivity in Bald Eagles from northern 71% in the Columbia estuary (Watson et al. 1991), Saskatchewan (Gerrard et al. 1992), as well as and 76-85% in southeastern Alaska (Ofelt 1975). Golden Eagles (Tjernberg 1983, Steenhof et al. While Watson et al. (1991) noted that several eagle 1997) and Gyrfalcons (Poole and Bromley 1988), pairs in the Columbia River estuary were “special- while hail storms caused >30% of the reproductive ists,” preferentially taking certain food species, failure in Swainson’s Hawks in North Dakota (Gil- such as waterfowl, relative to other eagle pairs, we more and Stewart 1984). found no such specialization. Any variation in diet Food availability may also impact nestling surviv- breadth could be traced to differences in local al indirectly. Adults with high prey-delivery rates food availability, such as the presence of large tidal have higher nest attendance, because eagles that flats near nests that consumed large numbers of are more successful hunting can spend less time plainfin midshipman. foraging (Watson et al. 1991), reducing eaglet We conclude that time of day, temperature, rain- mortality through predation or is exposure. This fall, and tide height all impact eagle provisioning particularly critical the first in- during 4 wk when rates, and therefore, adult nest attendance and creased nest attendance aids in nestling thermo- chick activity. Our results support the hypotheses regulation (Warnke et al. 2002). advanced by Elliott et al. (1998) and Gill and Elli- Brown (1993), Knight and Knight (1983), Han- ott (2003) that nesting success is greater on the sen (1986), Knight and Skagen (1988), Watson et east coast because there are more tidal flats and al. (1991), and Bennetts and McLelland (1997) fewer storms. Steenhof et al. (1997) documented showed that the ability of eagles to obtain food in- similar results for Golden Eagles in Idaho, in which creases with age. As with many other bird species, reproductive success was determined by prey reproductive success in raptors usually increases (black-tailed jackrabbit [Lepus californicus] abun- with age (Newton 1998); fecundity peaks at age 5 dance and weather (frequency of hot days) yr among Eurasian Sparrowhawks (Accipiter nisus; Newton and Rothery 2002) and at age 7 yr among Acknowledgments Northern Goshawks {Accipiter gentilis] Nielsen and C. Hurd, C. Coker, S. Lee, and R. Gill aided during Drachmann declining 2003), thereafter in both observations. D. Haycock climbed all nest trees with species. In addition adult-adult Spanish Imperial grace and style. D. and C. Braggins, the Mounts, R. Hop-

Eagle {Aquila adalberti) pairs monopolize high ping, A. and J. Caldwell, and S. Napier graciously allowed access to their property. D. Henry and G. Biscall provided quality territories, hence have higher average fe- valuable information on Bald Eagle use of their fish by- cundity than Juvenile-juvenile pairs (Ferrer and catch. The Canadian Wildlife Service, a Simon Fraser Bisson 2003). Therefore, older individuals presum- University Graduate Research Fellowship, and the Bald ably provision at higher rates than younger ones. Eagle Rescue and Research Foundation provided funding. We did not know the age of adults in our study, We are especially grateful to J. Bednarz, C. Dykstra, M. Hipfner, B. Steidl, K. Warnke, and Watson. and this factor may explain some of the variability J. Their comments greatly improved this manuscript. A. Fabro lo- between individual nests. cated some obscure literature. Examination of prey remains at nests from both study areas suggested that birds were the primary Literature Cited food source, as have most prey remains studies in Ann, H.B. 1973. Studies on the age and growth of the the Pacific Northwest (e.g., Norman et al. 1989, jack mackerel {Trachurus japonicus). Bull. Fish. Res Vermeer et al. 1989, Vermeer and Morgan 1989, Agency 10:73—82. Knight et al. Watson 1990, 2002). However, birds Anthony, R.G. 2001. Low productivity of Bald Eagles on made up less than 7% of prey at either location Prince of Wales Island, southeast Alaska. J. Raptor Res during our study, as revealed by direct observation. 35:1-8.

The major prey source at both locations in our , R.W. Frenzel, F.B. Isaacs, and M.G. Garrett /

8 Elliott et ai.. VoL. 39, No. 1

1994. Probable causes of nesting failures in Oregon’s food deliver rates or environmental contamination? Bald Eagle population. Wildl. Soc. Bull. 22:576-582. Great Lakes Res. 24:22—34.

, M.J. Garrett, and C.A. Schuler. 1993. Environ- Dzus, E.H. and J.M. Gerrard. 1993. Factors influencing mental contaminants in Bald Eagles in the Columbia Bald Eagle densities in north-central Saskatchewan./. River estuary./. Wildl. Manag. 57:10-19. Wildl. Manag. 57:771-778.

, A.K. Miles, J.A. Estes, and F.B. Isaacs. 1999. Pro- Elliott, J.E., I.E. Moul, and K.M. Cheng. 1998. Variable ductivity, diets, and environmental contaminants in reproductive success of Bald Eagles on the British Co- nesting Bald Eagles from the Aleutian archipelago. lumbia coast./. Wildl. Manag. 62:518-529. Environ. Toxicol. Chem. 18:2054—2062. Elliott, K.H., C.L. Struik, and J.E. Elliott. 2003. Bald Barton, N.W.H. and D.C. Houston. 1993. A comparison Eagles, Haliaeetus leucocephalus, feeding on plainfin of digestive efficiency in birds of prey. Ibis 135:363- midshipman, Porichthus notatus, at Crescent Beach 371. Can. Field-Nat. 117:601-604. Bennetts, R.E. B.R. McLelland. 1997. Influence of and Ferrer, M. and I. Bisson. 2003. Age and territory-quality age and prey availability on Bald Eagle foraging be- effects of fecundity in the Spanish Imperial Eagle {Aq- Wilson Bull. havior at Glacier National Park, Montana. uila adalberti). Auk 120:180—186. 109:393-409. Fritz, H. 1998. Wind speed as a determinant of klepto- develop- Bortolotti, G.R. 1984a. Physical growth and parasitism by Eurasian Kestrel Falco tinnunculus on ment of nestling Bald Eagles with emphasis on the Short-eared Owl Asio flammeus. J. Avian Biol. 29:331- timing of growth events. Wilson Bull. 96:524—542. 333.

. 1984b. Criteria for determining the age and sex Garrett, M.G., J.W. Watson, and R.G. Anthony. 1993. of nestling Bald Eagles./. Field Ornithol. 55:467-481. Bald Eagle home range and habitat use in the Colum- Bowerman, W.W., D.A. Best, J.P. Giesy, M.C. Shieldcas- bia River estuary./. Wildl. Manag. 57:19-27. tle, M.W. Meyer, S. Postupalsky, and J.G. Sikarskie. Gende, S.M., M.F. Wilson, and M. Jacobsen. 1997. Re- 2003. Associations between regional differences in po- productive success of Bald Eagles {Haliaeetus leucoce- lychlorinated biphenyls and dichlorodiphenyldichlo- phalus) and its association with habitat or landscape roethylene in blood of nestling Bald Eagles and re- features and weather in southeast Alaska. Can. J. Zool. productive productivity. Environ. Toxicol. Chem. 22: 75:1595-1604. 371-376. and M.F. Wilson. 1997. Supplemental feeding ex- Brown, B.T. 1993. Winter foraging ecology of Bald Eagles periments of nesting Bald Eagles in southeastern v\las- in Arizona. Condor 95:132-138. ka. /. Field Ornithol. 68:590-601. Dominguez, L., W.A. Montevecchi, N.M. Burgess, J. Gerrard, J.M., P.N. Gerrard, P.N. Gerrard, G.R. Bor- Brazil, and K.A. Hobson. 2003. Reproductive suc- tolotti, and E.H. Dzus. 1992. A 24-year study of Bald cess, environmental contaminants, and trophic status Eagles on Besnard Lake, Saskatchewan. /. Raptor Res of Bald Eagles nesting in eastern Newfoundland. /. 26:159-166. Raptor Res. 37:209-218. Gerrard, P.M., S.N. Wiemeyer, and J.M. Gerrard. 1979. Donaldson, G., J.L. Shutt, and P. Hunter. 1999. Or- Some observations on the behavior of captive Bald ganochlorine contamination in Bald Eagle eggs and Eagles before and during incubation. Raptor Res. 13: nestlings from the Canadian Great Lakes. Arch. Envi- 57-64. ron. Contam. Toxicol. 36:70—80. Gilchrist, H.G., AJ. Gaston, and J.N.M. Smith. 1998. Dugoni, J.A., PJ Zwank, and G.C. Furman. 1986. Food Wind and prey nest sites as foraging constraints on of nesting Bald Eagles in Louisiana. Raptor Res. 20: 124-125. an avian predator, the Glaucous Gull. Ecology 79:2403- 2414. Dvkstra, C.R., J.L. Havs, M.M. Simon, and F.B. Daniel. Effects of nest site 2003. Behavior and prey of nesting Red-shouldered AND A.J. Gaston. 1997. murre characteristics and wind conditions on predations by Hawks in southwestern Ohio. /. Raptor Res. 37:177- Zool. 75:518-524. 187. Glaucous Gulls. Can. J. Gill, C.E. and J.E. Elliott, 2003. Influence of food sup- , W.H. Karasov, M.W. Meyer, and D.K. Warnke. 2001a. Daily energy expenditure of nestling Bald Ea- ply and contaminants on breeding success of Bald Ea- gles in northern Wisconsin. Cowdor 103:175— 179. gles. Ecotoxicology 12:95-112. Gilmore, D.S. and R.E. Stewart. 1984. Swainson’s Hawk , M.W. Meyer, K.I.. Stromborg, D.K. Warnke, W.W. Bowerman, and D.A. Best. 2001b. Association Buteo swainsoni nesting ecology in North Dakota USA of low reproductive rates and high contaminant levels Condor 86:12-18. in Bald Eagles on Green Bay, Lake Michigan./. Great Grubb, T.G.J. 1977. Weather-dependent foraging in Os- Lakes Res. 27:239-251. preys. Auk 94:146-149. S. S. E. , , D.K. Warnke, W.H. Karasov, D.E. An- Hakkarainen, H., Mykra, Kurki, Korpimaki, A.

dersen, W.W. Bowerman, IV, and J.P. Giesy. 1998. Low Nikula, and V. Koivunen. 2003. Habitat composition reproductive rates of Lake Superior Bald Eagles: low as a determinant of reproductive success of Teng- .

March 2005 Bald Eagle Provisioning Rates 9

malm’s Owls under fluctuating food conditions. Oikos Horned Owl and Red-tailed Hawk in central Alberta, 100:162-171. Canada. Can. Field-Nat. 88:1-20.

Hancock, D. 1964. Bald Eagles wintering in the southern Mersmann, T.J., D.A. Buehler, J.D. Fraser, and J.KD. Gulf Islands, British Columbia. Wibon Bull. 76:117- Seegar. 1992. Assessing bias in studies of Bald Eagle Wildl. 56:73—78. 120 . food habits, y. Manag.

Hansen, A.J. 1986. Fighting behavior in Bald Eagles: a Newton, I. 1978. Feeding and development of Sparrow test of game theory. Ecology 67:787-797. Hawk Accipiter nisus nestlings./. ZooZ. Fond. 184:465- 488. . 1987. Regulation of Bald Eagle reproductive

rates in southeastern Alaska. Ecology 68:1387—1392. . 1979. Population ecology of raptors. Buteo Harper, D.M., M.M. Harper, M.A. Virani, A. Smart, R.B. Books, Vermillion, SD U.S.A.

. 1998. Population limitation in birds. Academic Childress, R. Adatia, I. Henderson, and B. Chege. 2002. Population fluctuations and their causes in the Press, San Diego, CA U.S.A. and P. Rothery. 2002. Age-related trends in dif- African Fish Eagle {Haliaeetus vocifer [Daudin] ) at Lake Naivasha, Kenya. Hydrobiologia 488:171-180. ferent aspects of the breeding performance of individual female Eurasian Sparrowhawks {Accipiter nisus) Helander, B. 1985. Reproduction of the White-tailed Sea Auk 119:735-748. Eagle Haliaeetus albicilla in Sweden. Holarct. Ecol. 8: Nielsen, Drachmann. 2003. Age-dependent 211-227. J.T. and J. reproductive performance in Northern Goshawks Ac- Hilton, G.M., D.C. Houston, and R.W. Furness. 1998. cipiter gentilis. Ibis 145:1-8. Which components of diet quality affect retention Norman, D., A.M. Breault, and I.E. Moul. 1989. Bald time of digesta in seabirds? Fund. Ecol. 12:929-939. Eagle incursions and predation at Great Blue Heron Jaksic, F.M., S.l. Silva, P.L. Meserve, and J.R. Gutierrez. colonies. Colon. Waterbirds 12:215-217. 1997. A long-term study of vertebrate predator re- Ofelt, C.H. 1975. Food habits of nesting Bald Eagles in sponse to an El Nino (ENSO) disturbance in western southeast Alaska. Condor 77:337-338. South America. Oikos 78:341-354. Panasci, T. and D. Whitacre. 2000. Diet and foraging Jenkins, M.J. 1989. Behaviour of nestling Bald Eagles. behavior of nesting roadside hawks in Peten, Guate- Bird Behav. 8:23-31. mala. Wilson Bull. 122:555—558. Kennedy, E, and I. McTaggart-Cowan. 1998. Sixteen Piatt, J.B. 1976. Gyrfalcon nest site selection and winter years with a Bald Eagle’s, Haliaeetus leucocephalus, nest. activity in the western Canadian arctic. Can. Field-Nat Can. Field-Nat. 112:704-706. 90:338-345. Knight, R.L. and S.K. Skagen. 1988. Agonistic asymme- Poole, K.G. and R.G. Bromley. 1988. Natural history of tries and the foraging ecology of Bald Eagles. Ecology the Gyrfalcon in the central Canadian arctic. ArcticAX 69:1188-1194. 31-38.

, Randolph, G.T. Ailen, L.S. Young, and PJ. R.J. Ridpath, M.G. and M.G. Brooker. 1986. The breeding WiGEN. 1990. Diets of nesting Bald Eagles, Haliaeetus of the Wedge-tailed Eagle Aquila audax in relation to leucocephalus, in western Washington. Can. Field-Nat. its food supply in arid western Australia. Ibis 128:177- 104:545-551. 194. 1983. Aspects Knight, S.K. and R.L. Knight. of food Seavy, N.E., M.D. Schulze, D.F. Whitacre, and M.A. Vas- finding by wintering Bald Eagles. Auk 100:477—484. QUEZ. 1998. Breeding biology and behavior of the E. 1992. Diet composition, choice, Korpimaki, prey and Plumbeous Kite. Wilson Bull. 110:77-85. breeding success of Long-eared Owls: effects of mul- Smith, D.G., J.R. Murphy, and N.D. Woefinden. 1981 tiannual fluctuations in food Zool. abundance. Can. J. Relationships between jackrabbit Lepus californicus 70:2373-2381. abundance and Ferruginous Hawk Buteo regalis repro- Kruger, O. and J. Lindstrom. 2001. Habitat heteroge- duction. Condor 83:52-56. neity affects population growth in goshawk Accipiter Stalmaster, M.V. and J.A. Gessaman. 1984. Ecological gentilis. J. Anim. Ecol. 70:173-181. energetics and foraging behavior of overwintering Kumar, K.S., K. Kannan, J.P. Giesy, and S. Masunaga. Bald Eagles. Ecol. Monogr. 54:407-428. 2002. Distribution and elimination of polychlorinated Steenhof, K., M.N. Kochert, and T.L. McDonai.d. 1997. dibenzo-p-dioxins, dibenzofurans, biphenyls, and p,p’- Interactive effects of prey and weather on Golden Ea- DDE in tissues of Bald Eagles from the Upper Pen- gle reproduction. J. Anim. Ecol. 66:350-362. insula of Michigan. Env. Sci. Tech. 36:2789-2796. Steidl, R.J., K.D. Kozie, and R.G. Anthony. 1997. Re- McDonald, P.G., P.D. Olsen, and A. Cockburn. 2004. productive success of Bald Eagles in interior Alaska Weather dictates reproductive success and survival in J. Wildl. Manag. 61:1313-1321.

the Australian Brown Falcon Falco berigora. J. Anim. Stinson, C.H. 1980. Weather-dependent foraging success Ecol. 73:683-692. and sibling aggression in Red-tailed Hawks in central McInvaille, W.B., Jr. and L.B. Keith. 1974. Predator Washington. Condor 82:76-80. prey relations and breeding biology of the Great Stout, J.H. and K.A. Trust. 2002. Elemental and organ- 10 Elliott et al. VoL. 39, No. 1

ochlorine residues in Bald Eagles from Adak Island, Warnke, D.K., D.E. Andersen, C.J.R. Dykstra, M.W. Mey- Alaska./. WMl Dis. 38:511-517. er, AND W.H. Karasov. 2002. Provisioning rates and Tjernberg, M. 1983. Prey abundance and reproductive time budgets of adult and nestling Bald Eagles at in- success of the Golden Eagle Aquila chrysaetos in Swe- land Wisconsin nests. / Raptor Res. 36:121-127. den. Holart. Ecol. 6:17-23. Watson, J.W. 2002. Comparative home ranges and food Touchton, J.M., H.Y. Cheng, and A. Palleroni. 2002. habits of Bald Eagles nesting in four aquatic habitats Foraging ecology of reintroduced captive-bred sub- in western Washington. Northwest. Nat. 83:101-108.

adult Harpy Eagles {Harpia harpyja) on Barro Colo- , M.G. Garrett, and R.G. Anthony. 1991. Forag- rado Island, Panama. Ornitol. Neotrop. 13:365—379. ing ecology of Bald Eagles in the Columbia River es- Todd, C.S., L.S. Young, R.B. Owen, Jr., and F.J. Gram- tuary. / Wildl. Manag. 55:492-499.

LICH. 1982. Food habits of Bald Eagles in Maine. /. , S.R. Rae, and R. Stillman. 1992. Nesting density Wildl. Manag. 46:636-645. and breeding success of Golden Eagles in relation to van Daele, LJ. and H.A. van Daele. 1982. Factors af- food supply in Scotland./. Anim. Ecol. 61:543-550.

fecting the productivity of Ospreys Pandion Haliaetus Wiehn, J. and E. Korpimaki. 1997. Food limitation on nesting in west central Idaho USA. Condor 84:292-299. brood size: experimental evidence in the Eurasian Vermeer, K. and K.H. Morgan. 1989. Nesting popula- Kestrel. Ecology 78:2043-2050.

tion, nest sites, and prey remains of Bald Eagles nest- Wilson, M.F. and R.H. Armstrong. 1998. Intertidal for- ing in Barkley Sound, British Columbia. Northwest. aging for Pacific Sand-Lance, Ammodytes hexapterus, by Nat. 70:21-26. birds. Can. Field-Nat. 112:715-716.

, , R.W. Butler, and G.E.K. Smith. 1989. Wright, J., C. Both, P.A. Cotton, and D. Bryant. 1998. Population, nesting habitat, and food of Bald Eagles Quality vs. quantity: energetic and nutritional trade- in the Gulf Islands. Pages 123-130 in K, Vermeer and offs in parental provisioning strategies. / Anim. Ecol R.W. Butler [Eds.], The ecology and status of marine 67:620-634. and shore birds in the Strait of Georgia, British Co- lumbia. Special Publication, Canadian Wildlife Ser- Received 16 April 2004; accepted 31 October 2004 vice, Ottawa, Ontario, Canada. Associate Editor: James W. Watson Res. J. Raptor 39(1):11—18 © 2005 The Raptor Research Foundation, Inc.

FIRST COMPLETE MIGRATION CYCLES EOR JUVENILE BALD EAGLES {HALIAEETUS LEUCOCEPHALUS) FROM LABRADOR

Dawn K. Laing and David M. Bird Avian Science and Conservation Centre, McGill University, 21,111 Lakeshore Road, Ste. Anne de Bellevue, Quebec, H9X 3V9, Canada

TonyE. Chubbs Department of National Defence, 5 Wing Goose Bay, Box 7002, Station A, Happy Valley-Goose Bay, Labrador, Newfoundland AOP ISO, Canada

Abstract.—^We documented complete annual migratory cycles for five hatch-year Bald Eagles {Haliaeetus leucocephalus) from central Labrador, Canada. We attached backpack-mounted Platform Transmitter Ter- minals (PTT) to track hatch-year eagle movements from their natal areas. The median departure date from natal areas was 26 October 2002, with the earliest departure occurring on 7 October 2002 and the latest on 12 November 2002. All eagles migrated independently of siblings and spent a mean of 62 d on autumn migration at a mean speed of 45 km/hr with a mean of hve stopovers. Eagles travelled north in the spring at an estimated speed of 27 km/hr over 32 d, with a maximum of 1 1 stopovers. One wintered

in the Gulf of St. Lawrence, while the remaining eagles migrated to the northeastern U.S.A. Eagles spent a mean of 76 d on their wintering grounds, with a median date of departure for spring migration of 20 March 2003. Two of the eagles returned to Labrador during their first summer and showed some fidelity to their natal areas. We document migration routes and identify stopover areas.

Key Words: Bald Eagle, Haliaeetus leucocephalus; migration', juvenile, satellite telemetry, stopover, dispersal', Labrador.

PRIMEROS CICLOS MIGRATORIOS COMPLETOS PARA INDfVIDUOS JUVENILES DE HALIAEETUS LEUCOCEPHALUSm. LABRADOR

Resumen.—En este estudio documentamos los ciclos migratorios anuales completes para cinco individuos de la especie Haliaeetus leucocephalus durante su ano de eclosion en Labrador central, Canada. Para seguir los movimientos de las aguilas desde su lugar de nacimiento, les acoplamos terminales transmi- soras de plataforma por medio de morrales. La mediana de la fecha de partida de las areas natales fue el 26 de octubre de 2002. El abandono mas temprano sucedio el 7 de octubre y el mas tardfo el 12 de noviembre de 2002. Todas las aguilas raigraron independientemente de sus hermanos y permanecieron en promedio 62 dfas en migracion de otono a una velocidad media de 45 km/hr, realizando un promedio de cinco paradas durante la migracion. Las aves viajaron hacia el norte en la primavera a una velocidad estimada de 27 km/hr a lo largo de 32 dfas, con un maximo de 11 paradas. Una de ellas paso el invierno en el Golfo de St. Lawrence, mientras que las demas migraron al noreste de los Estados Unidos. Las aguilas pasaron un promedio de 76 dfas en sus areas de invernada, y la mediana de la fecha de partida para la migracion de primavera fue el 20 de marzo de 2003. Dos de los individuos regresaron a Labrador en su primer verano y mostraron cierta fidelidad a sus areas de nacimiento. Tambien documentamos las rutas de migracion y las areas importantes de escala migratoria. [Traduccion del equipo editorial]

A southward migration of post-fledging Bald Ea- results (Gerrard et al. 1992). With the advance- gles {Haliaeetus leucocephalus) from northern Ca- ment of satellite-telemetry technology, information nadian natal areas to southern wintering grounds on the ecology and life history of raptors has been has long been known (Gerrard et al. 1978). Band- greatly expanded beyond what could possibly be ing and radiotagging eagles have produced limited gathered during decades of conventional telemetry

and banding (Meyburg et al. 1995, Ueta et al. 2000,

^ Email address: [email protected] Hake et al. 2001, I^ellen et al. 2001). Using both

11 . ,

12 Laing et al. VoL. 39, No. 1 banding data and conventional telemetry, dispersal from the nest to an adjacent area, where birds were processed and banded. Once captured, eagles were fitted behavior, movements, and survival ofjuvenile Bald with 95-g, battery-powered PTT-100 transmitters (Micro- from Florida (Wood Eagles have been documented wave Telemetry Inc., Columbia, MD U.S.A.) affixed in a et al. 1998), Saskatchewan (Gerrard et al. 1978, backpack harness fashion using Teflon ribbon (Bally Rib- Harmata et al. 1985), Wyoming, California (Hunt bon Mills, Bally, PA U.S.A.). Each transmitter was set with a preset duty cycle to transmit to satellite more frequently et al. 1992), Texas (Mabie et al. 1994), and Colo- (8 hr on, 48 hr off) during possible periods of migration, rado (Harmata 2002) . Little is known about eagle most frequently during October and March and less fre- activities beyond their first winter, limiting our quently during summer and winter months. All eagles knowledge pertaining to juvenile stopover habitats, were banded with a U.S. Geological Survey aluminium- tarsus a colored-metal-alphanu- migratory flyways (McClelland et al. 1994, 1996), rivet band on one and meric-rivet band (Acraft Sign and Nameplate Co. Ltd., and sources of possible mortality (Buehler et al. Edmonton, Alberta, Canada) on the other. little information is available 1991). Furthermore, We monitored eagle movements using the Argos Data distribution, nesting chronology, and mi- regarding Collection services (ARGOS 2000) . We determined nest- gration timing and routes on the eastern Canadian ing sites, stopover details, wintering areas, and migration population of Bald Eagles in Labrador. routes using the location data received via satellite. Prior to processing, we put location data into a database using Wetmore and Gillespie (1976) conducted initial a Geographic Information System (GIS), and movement since investigations of Bald Eagles in Labrador, and was then analyzed using ESRI® ArcView 3.2 (ESRI, Red- 1991, the Canadian Department of National De- lands, CA U.S.A.) in combination with the Animal Move- fence (DND) has been monitoring nest sites and ment Extensions program (Hooge and Eichenlaub Argos System divides data into different productivity through annual surveys (DND 1995). 1997). The classes based on validation and number of messages re- To date, there are some 30-40 known Bald Eagle ceived. Location classes (LC) are ranked by accuracy nest sites in Labrador (T. Chubbs unpubl. data). (3>2>1>0>A>B>Z; accurate to least accurate) by Ar- As part of a larger study investigating the move- gos; however, we found that several locations per trans- ments of raptors within and out of Labrador mission period were sufficient to document raptor movements if reviewed individually. Location validity and (Laing et al. 2002), we implemented a satellite-te- accuracy were further determined by comparing consec- lemetry program to track five hatch-year Bald Ea- utive locations to previous locations resulting in a move- gles from August 2002-August 2003. ment estimate. Using this screening method we were able to include more than one transmission per reporting pe- Study Area and Methods riod, independent of location class and quality index Therefore, based on existing literature demonstrating Our study took place within the Low Level Training mean juvenile eagle rates of movement (Buehler 2000), Area (LLTA) for fighter aircraft, covering an area of ca. if estimate report- 130 000 km^ spanning the Labrador-Quebec northeast- we accepted a location the movement for bird was 0 but rejected it if the movement ern border. We searched for occupied raptor nests in the ed a km/d, estimate greater than 500 then compiled vicinity of the Smallwood Reservoir, ca. 6700 km^ of cen- was km/d. We a database comparing the number of locations used for tral Labrador. This area consists of water bodies, promi- this by location estimates nent rocky islands, isolated erratics, and rock outcrops. analysis and divided number received to a percentage of viable-satellite Surrounding the reservoir are shorelines under 1 m of determine not water and that are littered with driftwood, while beyond transmissions (LC Z-transmissions were removed and the waterline are stands of black spruce {Picea mariana) used in estimates). Wetlands in this low subarctic ecoclimate are subject As the transmitters were programmed following a pre- to permafrost. This region has a mean annual tempera- determined duty cycle (i.e., September-October 8 hr on ture of — 3°C, a mean summer temperature of — 9°C, and and 48 hr off, and November-December alternated be- a mean winter temperature of — 16°C (Meades 1990). De- tween 8 hr on and 72 hr off and 8 hr on and 168 hr off) pending on latitude, the mean annual precipitation exact dates of departure from nesting sites and arrivals ranges from 700-1000 mm (McManus and Wood 1991). at wintering grounds are unknown. To estimate dates of Bald Eagles typically nest along rivers and large reservoirs arrival we considered that a raptor migrating to an area in dominant white birch {Betula papyrifera), balsam fir had arrived by the first date a location was obtained from {Abies balsamea), larch (Larix laricina), poplar {Populus hal- that area. On departure its location was considered to be samifera), and black spruce at a height of 15-30 m (Bider the location estimate received from within the area. An and Bird 1983). We have observed eagle nests in all of area was considered to be a stopover site if we received these tree species in Labrador. location estimates from an area for at least 24 hr (I^ellen Rock pinnacles and trees are used by nesting Bald Ea- et al. 2001) and the bird demonstrated concentrated lo- gles in Labrador. However, due to the inaccessibility and calized movement. remoteness of tree nests, hatch-year eagles (8-10 wk) Distances travelled between summer and winter were captured from rock nests situated in lakes and res- grounds were calculated by adding the linear distances ervoirs. Nests were accessed using a ladder or by moun- from the departure point to the arrival location, includ- taineering techniques, and birds were removed by hand ing distances to and from stopover locations. We calcu- March 2005 Eagle Migration from Labrador 13 lated radial distances from capture sites using a 95% Ker- wintered in Virginia and West Virginia, respective- nel home-range estimator, with the Animal Movement ly. Eagle 37412 had four stopovers before reaching Extensions program (Hooge and Eichenlaub 1997), which determined an estimate of the area used by the its wintering grounds of Albany, NY, on 1 Decem- eagle. ber 2002, travelling more than 2444 km after leaving its natal area. Eagle 37415 had six stopovers Results prior to reaching its wintering grounds of Orange During the 2002 summer field season (15-30 Au- County, VA, on 5 February 2003, ca. 1370 km from gust) five juvenile eagles were captured and fitted its natal area. with PTTs. We recorded 6472 locations between 15 Eagles 37411 and 37413 (Fig. 1) left the Gulf of August 2002-30 August 2003. Of these, 75% were St. Lawrence and moved toward the U.S.A. east used in analysis. A mean of 966 locations per eagle coast, stopping along the borders of VT and NH. was collected with only the most-likely locations Eagle 37411 made 11 stopovers and travelled ca. plotted using CIS (0% Z, 20% B, 19% A, 32% 0, 1420 km before reaching its wintering grounds

22% 1, 5% 2, and 2% 3). Of those captured, eagles along the Hudson River between Ulster and Dutch- 37414 and 37413 and eagles 37412 and 37415 were ess counties, NY. Eagle 37413 travelled ca. 1640 km siblings, respectively, and 37411 was captured before settling in Hartford County, CT, with half alone. the number of stopovers. Movements before Fall Migration. Eagles re- Movements before Spring Migration. The mean mained within their natal area for a mean of 74 d overwintering period was 76 d, (44—124 d), except following transmitter attachment, with departures for 37414 which remained on wintering grounds. as early as 7 October 2002 and as late as 12 Novem- Spring Migration. We defined spring migration ber 2002, and a median departure date of 26 Oc- as the period of time in which the birds departed tober 2002. Each bird exhibited exploratory flight from wintering grounds and arrived at summering patterns, and used a mean range of 165 km^ (97- grounds. Once on the summering grounds, the ea- 252 km^) around original capture sites. gles did exhibit exploratory and nomadic flight be- Fall Migration. During autumn migration, the haviour. Eagle 37414 did not migrate in the spring; eagles averaged five stopovers prior to reaching however, it moved within the same 252 km^ area their wintering destinations, with stays ranging be- for the whole summer and did not venture away tween 24 hr and 25 d. The eagles took between 5- from the Gulf of St. Lawrence. 95 d to reach their wintering areas, with straight- Departure dates for the four remaining eagles line distances between natal areas and wintering were between 11-27 March 2003. The birds had areas ranging from 510-930 km (Fig. 2). two to six stopovers prior to reaching the Gulf of

Eagle 37414 (Fig. 1) travelled the shortest linear St, Lawrence. Three of the four eagles (Fig. 2) route south, probably departing its nest site on 13 used similar routes as taken during fall migration November 2002. Generally, the relatively infre- to travel north, with the exception of 37415 which quent location estimates from Argos were insuffi- travelled more easterly. Eagle 37415 did not stop cient for tracking the birds’ routes, and therefore, at Lake Ontario when travelling north in the there were likely deviations from a straight line. spring and meandered west of its original autumn However, during fall (and spring) migrations we route (Fig. 2). All of the eagles were tracked to the received location estimates as often as once every Gulf of St. Lawrence; two eagles continued further 2 d, suggesting that our estimates represented fair north to the Quebec and Labrador border for the delineations of movement. The next transmission summer. All four birds arrived at the north shore date for eagle 37414, 18 November 2002, was lo- of Gaspe, Quebec, between 11-30 April 2003, av- cated along the northern coast of the Gulf of St. eraging 32 d on migration.

Lawrence, 472 km from its natal area. This bird Eagle 37413 left its wintering ground first on 10 wintered, and remained, in the gulf area through March 2003, travelling northeasterly for 1100 km the spring migration period. The remaining four with three stopovers and arriving at the Gulf of St. eagles stopped along the north shore in Quebec, Lawrence on 21 April 2003. Comparatively, eagles continued southwest, and avoided crossing the 37412 and 37415 left their wintering grounds at Gulf of St. Lawrence. similar times and travelled 1955 km and 1600 km

Eagles 37412 and 37415 (Fig. 1) took similar to arrive at the Gulf of St. Lawrence on 21 and 26 routes southwest, stopped at Lake Ontario, and April 2003, respectively. Eagle 37411 left its winter- 14 Laing et al. VoL. 39, No. 1 4 L »LAB^ 5 Nov 02

Figure 1. Fall migratory routes of juvenile Bald Eagles from their natal sites in Labrador to their wintering grounds as tracked by satellite in 2002. March 2005 Eagle Migration from Labrador

Figure 2. Spring migratory routes of juvenile Bald Eagles from their wintering sites to their summering grounds tracked by satellite in 2003. 16 Laing et al. VoL. 39, No. 1 ing grounds the latest (26 March 2003), and trav- linked to weather or foraging opportunities. Be- elled 790 km to its summering grounds with three cause all five eaglets were captured at the same lat- stopovers to arrive at the Gulf of St. Lawrence on itude and longitude, they were exposed to many of 9 April 2003. the same weather conditions. Therefore, weather Eagle 37413 divided its summer activities be- characteristics such as the first snow fall or frost tween the Gulf of St. Lawrence and New York State. event could have contributed by triggering the ini- Eagle 37415 was located on the Quebec and New tiation of migration of individuals. Conversely, Har- Brunswick borders on 1 May 2003 (Eig. 2) and mata et al. (1999) stated that juveniles may exhibit moved south again to New York on 15 May 2003. movement that is individually characteristic of the It then returned to the Gulf of St. Lawrence on 8 juvenile and exclusive of foraging opportunities.

June 2003. On 12 August 2003, this bird began Montana juvenile eagles (McClelland et al. moving south to New York. 1996) departed their natal territories between 22 Eagles 37411 and 37412 left the Gulf of St. Law- August—5 October (median = 9 September, N ~ rence between 3-6 May (Eig. 2). Eagle 37411 Saskatchewan juveniles left at the 2003 5) , beginning of flew 400 km to the Caniapiscau Reservoir (Que- October (Gerrard et al. 1978), and a population bec) and later spent time at the Ossokmanuan Res- in southern California departed between 19 July- ervoir (Labrador). Eagle 37412 travelled 617 km 22 August (Hunt et al. 1992). More northern stud- north and spent its summer at the Smallwood Res- ies have documented movement from northern ervoir. Saskatchewan as late as 3 November (Harmata et

All eagles moved sporadically during the sum- al. 1999). Generally, Labrador eagles migrated mer period, with most location estimates indicating south late in the season (median = 26 October). activities on the north shore of the Gulf of St. Lawr- While the four eaglets travelled independently ence. of one another, some went in a similar direction

(i.e., southwest of natal areas), moving between Discussion lakes and rivers and exploiting aquatic environ- The departure ofjuvenile Bald Eagles from their ments. They made several stopovers along the way, natal nest sites in Labrador has become more pre- most near larger water-bodies such as the Gulf of dictable with the application of satellite technolo- St. Lawrence, Lake Ontario, and Lake Champlain. gy. Juvenile Bald Eagles from Labrador migrated Gerrard et al. (1978) believed that juveniles fol- south or southwest, consistent with previous juve- lowed rivers and were found near lakes as these nile Bald Eagle migration reports (Gerrard et al. areas represented favourable habitat. Montana ea- 1978, 1992, Hunt et al. 1992, McClelland et al. gles also made stops, sometimes for weeks at a

1994, 1996, Harmata et al. 1999, Harmata 2002). time, enroute to wintering areas (McClelland et al. Autumn movement was south toward the Gulf of 1994, 1996). These stops provided an opportunity St. Lawrence prior to dispersing en route to win- for eaglets to replenish nutrients lost during mi- tering areas. gration. Restani et al. (2000) elaborated on the We know from previous studies that juvenile mi- functional response on stopovers made by migrant gration may be initiated by changes in foraging op- Bald Eagles through Montana. They found that the portunities (Hodges et al. 1987, Hunt et al. 1992, eagles stopped while passing through a corridor, McClelland et al. 1994, Restani et al. 2000, Hoff- 80-130 km wide, around the Hauser Reservoir, man and Smith with birds departing an area Glacier National Park. eagles detected conspe- 2003) , The if prey is not readily available. Hunt et al. (1992) cifics foraging from 40-65 km away and then trav- suggested that eaglets first leave on exploratory or elled into the area to feed. The birds used this res- foraging flights and return to nest sites throughout ervoir as a stopover during both northward and the day for possible food provisioning by adults. southward migrations. We documented the use of What specific cue triggers migration in Labrador the St. Lawrence River and the Gulf of St. Law- eagles is not known. In the weeks following fledg- rence as both spring and autumn migration stop- ing, all five juvenile eagles remained in natal areas overs for Labrador juvenile eagles. The mean trav- and exhibited exploratory flights within a 40-km elling distance from wintering to summering radius of original nest areas, occasionally returning grounds was 350 km less than the distances trav- to the nest. elled from natal areas to winter grounds. We sus- Autumn departure may have been partially pect that Labrador eagles gained experience dur- .

March 2005 Eagle Migration from Labrador 17 ing their autumn migration, and that their flight fence Headquarters Project Office, Ottawa, Ontario, routes and strategies were more defined and less Canada. Gerrard, D.W.A. Whitfield, P. Gerrard, Ger- nomadic in the spring. Eagles may improve their J.M., P.N. rard, AND W.J. Maher. 1978. Migratory movements sense of direction on northern flights through vi- and plumage of subadult Saskatchewan Bald Eagles sual cues, mentally catalogued stopovers (Hake et CMn. Field-Nat. 92:375-382. al. 2001), and increased flight experience. , P.N. Gerrard, G.R. Bortolotti, and E.Z. Dzus. Spring departure of juveniles occurred between 1992. A 24-year study of Bald Eagles on Besnard Lake, 11-27 March 2003, and the four migrating eagles Saskatchewan./. Raptor Res. 26:159—166. used the Gulf of St. Lawrence fall stopover (me- Hake, M., N. I^ellen, and T. Alerstam. 2001. Satellite dian = 21 April 2003) prior to arriving at sum- tracking of Swedish Ospreys Pandion haliaetus: autumn mering grounds (between 3-6 May 2003). Non- migration routes and orientation./. Avian Biol. 32:47- breeding birds are more apt to spend time away 56. Harmata, A.R. 2002. Vernal migration of Bald Eagles from optimal nesting areas and focus on favour- from a southern Colorado wintering area. /. Raptor able foraging sites rather than establishing a breed- Res. 36: 256-264. ing territory (Jenkins et al. 1999). Based on the Toepfer, and GERRard. 1985. Fall mi- , J.E. J.M. survival of our five PTT-tagged birds, the Gulf of gration of Bald Eagles produced in northern Sas- St. Lawrence was a suitable stopover site, and pro- katchewan. Blue Jay 43:232-237. vided adequate foraging habitat for travelling Bald , F. Montopoli, B. Oakleaf, P. Harmata, and M. Eagles. Restani. 1999. Movements and survival of Bald Eagles banded in the greater Yellowstone ecosystem. /. Wildl Acknowledgments Manag. 63:781-793. Hodges, J.L, E.L. Boeker, and A.J. Hansen. 1987. Move- This project would not have been possible without the ments of radiotagged Bald Eagles, Haliaeetus leucoce- funding support of the Goose Bay Office, Department of National Defence, Canada. We also acknowledge the sup- phalus, in and from southeastern Alaska. Can. Field- port of McGill University, Gary Humphries, and the De- Nat. 101:136-140. partment of Tourism, Culture and Recreation (Endan- Hoffman, S.W. and J.P. Smith. 2003. Population trends gered Species and Biodiversity Section). We thank M. of migratory raptors in western North America, 1977- Solensky for demonstrating proper transmitter attach- 2001. Con^/or 105:397-419. ment techniques and for assisting in the field. We thank Hooge, P.N. AND B. Eichenlaub. 1997. Animal move- P. for their in L. Elson, G. Goodyear, and Trimper help ment extension to ArcView, Ver. 1.1. Alaska Biological the field. are grateful to Capt. (N) K.D. Laing for his We Science Center, U.S. Geological Survey, Anchorage, editorial assistance. We also thank M. Fuller, M. Restani, AK U.S.A. and M. Goldstein for comments that greatly improved Hunt, W.G., R.E. Jackman, J.M. Jenkins, C.G. Thelan- the manuscript. der, and R.N. Lehman. 1992. Northward post-fledging Literature Cited migration of California Bald Eagles. /. Raptor Res. 26. 19-23. Argos. 2000. User’s manual. Service Argos, Inc., Largo, Jenkins, J., R. Jackman, and W. Hunt. 1999. Survival and MD U.S.A. movements of Bald Eagles fledged in northern Cali-

Bider, J.R. AND D.M. Bird. 1983. Distribution and densi- fornia. /. Raptor Res. 33:81-86.

ties of Osprey populations in the Great Whale Region I^ellen, N., M. Hake, and I. Alerstam. 2001. Timing and of Quebec. Pages 223-230 in D.M. Bird, N.R. Sey- speed of migration in male, female, and juvenile Os- mour, andJ.M. Gerrard [Eds.], Biology and manage- preys Pandion haliaetus between Sweden and Africa as ment of Bald Eagles and Ospreys. Harpell Press, Ste. revealed by field observations, radar and satellite Anne de Bellevue, Quebec, Canada. tracking./. Avian Biol. 32:57-67. Buehler, D.A. 2000. Bald Eagle {Haliaeetus leucocephalus) Laing, D.K., D. Bird, T. Chubbs, and G. Humphries In A. Poole and F. Gill [Eds.], The birds of North 2002. Migration routes, timing, and nest site fidelity America, No. 506. American Ornithologists’ Union, of Osprey {Pandion haliaetus) and Bald Eagles {Hal- Washington, DC U.S.A. iaeetus leucocephalus) as they relate to military aircraft

, J.D. Fraser, J.K.D. Seegar, and G.D. Therres. activity in Labrador. Pages 82-92 in B. MacKiinnon 1991. Survival rates and population dynamics of Bald and K. Russell [Eds.], BirdStrike 2002 conference

Eagles on Chesapeake Bay. J. Wildl. Manag. 55:608- proceedings, August 19-21 2002. Transport Canada, 613. Toronto, Ontario, Canada. Department of National Defence. 1995. An environ- Mabie, D.W., M.T. Merending, and D.H. Reid. 1994. Dis-

mental impact statement on military flying activities persal of Bald Eagles fledged in Texas. /. Raptor Res in Labrador and Quebec. Goose Bay National De- 28:213-219. 18 Laing et al. VoL. 39, No. 1

McClelland, B.R., L.S. Young, P.T. McClelland, J.G. Restani, M., a. Harmata, and E. Madden. 2000. Numer- Crenshaw, H.L. Allen, and D.S. Shea. 1994. Migra- ical and functional responses of migrant Bald Eagles tion ecology of Bald Eagles from autumn concentra- exploiting a seasonally concentrated food source. Con- tion in Glacier National Park, Montana. Wildl. Monogr. dor 102:561-568. 125:1-61. Ueta, M., F. Sato, H. Nakagawa, and N. Mita. 2000 — P.T. McClelland, R.E. Yates, E.L. Caton, and , Migration routes and difference of migration sched- M.E. McFadzen. 1996. Fledging and migration of ju- ule between adult and young Steller’s Sea Eagles Hal- venile Bald Eagles from Glacier National Park, Mon- iaeetus pelagicus. Ibis 142:35-39. tana. Raptor Res. 30:70-89. J. Wetmore, S.P. and D. Gillespie. 1976. Osprey and Bald McManus, G.E. and C.H. Wood. 1991. Adas of New- Eagle populations in Labrador and northeastern Que- foundland and Labrador. Breakwater, St.John’s, New- bec, 1969-73. Can. Field-Nat. 90:330-337. foundland, Canada. Wood, P.B., M.W. Collopy, and C.M. Sekerak. 1998. Meades, S.J. 1990. Natural regions of Newfoundland and Postfledging nest-dependence period for Bald Eagles Labrador. Protected Areas Association, St. John’s, Newfoundland, Canada. in Florida./. Wildl. Manag. 62:333-339.

Mevburg, B.-U., J. Mendelsoun, D. Ellis, D. Smith, C. Meyburg, and a. Kemp. 1995, Year-round movements of Wahlberg’s Eagle Aquila wahlbergi tracked by satel- Received 23 March 2004; accepted 16 November 2004

INVESTIGATING FALL MOVEMENTS OF HATCH-YEAR FLAMMULATED OWLS (OTUS FLAMMEOLUS) IN CENTRAL NEW MEXICO USING STABLE HYDROGEN ISOTOPES

John P. DeLong^ HawkWatch International, 1800 S. West Temple, Suite 226, Salt Lake City, UT 84115 U.S.A.

Timothy D. Meehan^ and Ruth B. Smith^ Department of Biology, University of New Mexico, Albuquerque, NM 87131 U.S.A.

Abstract.—The migratory patterns of Flammulated Owls {Otus flammeolus) are poorly understood. We predicted natal origins of hatch-year Flammulated Owls captured from August-October in central New Mexico using stable hydrogen-isotope analysis of feathers. We collected reference feathers {N = 22) from Utah, Colorado, New Mexico, and Arizona and described the relationship between the 8D (stable hydrogen isotope ratio in parts per thousand [%o]) values in the feathers and the predicted 8D values for precipitation where the feathers were grown. We then used this relationship to determine the po-

tential origins of feathers taken from hatch-year owls captured during fall. We collapsed our results into three categories. Owls in the first category (with the least negative 8D values; N = 45) had feather- isotope ratios that corresponded with areas of central New Mexico and central Arizona, including the fall-banding site itself. Owls in the second category {N = 10) likely originated in northern New Mexico. Owls in the third category (most negative hD values; N = 2) originated either in the highest elevations of northern New Mexico, or more likely, in southern Colorado. These results indicated that some owls made at least 200 km movements to reach the study site, but that most captured owls likely originated locally or in adjacent mountain ranges.

Key Words: Flammulated Owl; Otus flammeolus; stable-hydrogen isotopes; migration patterns; geographical- catchment area.

INVESTIGACION DE LOS MOVIMIENTOS DE OTONO DE OTUS FLAMMEOLUS EN SU ANO DE ECLOSION EN EL CENTRO DE NEW MEXICO USANDO ISOTOPOS ESTABLES DE HIDROGENO

i?ESUMEN. —Los patrones migratorios de Otus flammeolus son poco conocidos. En este estudio usamos analisis de isotopos estables de las plumas para predecir los lugares de nacimiento de individuos de memos de un ano de edad de O. flammeolus capturados desde agosto hasta octubre en el centre de New Mexico. Colectamos plumas de referenda {N = 22) en Utah, Colorado, New Mexico y Arizona y describimos la relacion entre los valores de 8Z> (cociente del isotopo estable de hidrogeno en partes por mil [%o]) en las plumas y los valores predichos de 8D para la precipitacion de los lugares donde se desarrollaron las plumas. Luego usamos esta relacion para determinar el origen potencial de plumas tomadas de individuos capturados durante el otono. Resumimos nuestros resultados en tres categorias. Las lechuzas en la primera categoria (con los valores de 8D menos negativos; N = 45) presentaron cocientes de pluma-isotopo que correspondieron a las areas del centro de New Mexico y del centro de Arizona, incluyendo el sitio de anillado de otono. Las lechuzas en la segunda categoria {N = 10) probablemente se originaron en el norte de New Mexico. Las lechuzas en la tercera categoria (los valores de hD mas negativos; N = 2) se originaron o en las maximas elevaciones del norte de New Mexico, o mas probablemente, en el sur de Colorado. Estos resultados indicaron que algunas

^ Present address and corresponding author: 2314 Hollywood Ave. NW, Albuquerque, NM 87104 U.S.A.; Email’ [email protected] 2 Present address: Department of Sciences and Conservation Studies, College of Santa Fe, 1600 St. Michaels Dr., Santa Fe, NM 87505 U.S.A. ^ Present address: 2252 Calle Cuesta, Santa Fe, NM 87505 U.S.A.

19 20 DeLong et al. VoL. 39, No. 1

lechuzas realizaron movimientos de al raenos 200 km para llegar al sitio de estudio, pero que la mayoria de los individuos capturados probablemente se originaron localmente o en las cadenas mon- tanosas adyacentes. [Traduccion del equipo editorial]

Bird migration is a complex phenomenon that igin, or are they primarily migrants from far north has attracted considerable research attention for of the local breeding area? Second, is the seasonal decades (Able 1999). The migration of some birds pattern of owl captures related to the origins of the remains poorly understood, however. The Flam- owls? Third, are there sex differences in seasonal mulated Owl ( Otusflammeolus) is a small, nocturnal timing of capture or in natal origins? bird whose migration patterns are among the least Methods known in North America (McCallum 1994). The Field Methods. The study site was located near Capilla available evidence suggests that these owls are Neo- Peak in the Manzano Mountains of central New Mexico tropical migrants (McCallum 1994). This view is (34°42'N, 106°24'W; Fig. 1; DeLong and Hoffman 1999). derived primarily from the near absence of winter We captured owls at two netting stations spaced ca. 200 apart on the east west sides of the Capilla Peak records for Flammulated Owls in North America. m and Ridge. We lured owls to the stations with broadcast Flam- These negative results have not been accompanied mulated Owl calls placed within an array of three to six by positive data demonstrating where Flammulated mist nets (60-mm mesh). We opened mist nets 3-7 Owls in North America spend the winter. We que- nights/wk from 19 August-20 October 2002, for a total of 51 nights of netting. began netting ca. 0—30 ried the Bird Banding Laboratory database and We min after sunset and continued until 15-30 min before sun- found that, through the year 2000, no band recov- rise, or for shorter periods if inclement weather forced eries were obtained that directly documented the station closure. We generally opened nets only during migratory movements of Flammulated Owls. calm or moderately-windy periods, avoiding periods of high We investigated the natal origins of Flammulated wind (exceeding ca. 24 km/hr). We collected a contour feather from about every other Owls captured in the Manzano Mountains of cen- owl {N = 57) for use in the isotope analysis. Because tral New Mexico using stable-hydrogen-isotope isotope ratios in adult raptor feathers may not corre- analyses. Briefly, the latitudinal gradient in stable- spond to local precipitation (Meehan et al. 2003), we hydrogen-isotope ratios (^H/^H) associated with collected feathers only from hatch-year owls. Hatch-year Flammulated Owls leave the nest in juvenal plumage and growing season precipitation (SD^ is reflected in begin molting into formative plumage within about 1 wk animal tissues that are grown in those areas (Hob- after fledging (Reynolds and Linkhart 1987) . When they son and Wassenaar 1997). Although some hydro- are captured at the Capilla Peak banding station, most gen in tissues can exchange with atmospheric hy- hatch-year owls have not completed this molt (DeLong 2004). Therefore, we aged owls as hatch-years if they drogen (Wassenaar and Hobson 2000), for tissues showed a mix of juvenile and formative feathers and col- such as feathers and hair these ratios are more or lected only juvenile-plumage feathers for use in the sta- less locked into their structure and can be mea- ble-hydrogen-isotope analysis. sured even when the animal travels great distances We took blood samples from owls for sex determination. We collected blood from the brachial vein using the (Chamberlain et al. 1997). Recent studies show tip of a needle and a capillary tube and transferred the that the ratio of stable-hydrogen isotopes in the sample into a microcentrifuge tube containing ethanol. keratin of bird feathers (8T>y) of individuals cap- Wildlife Genetics, Inc. (Nelson, British Columbia, Cana- tured during migration can be compared to maps da) analyzed the samples and determined the sex of these owls using the CHD gene (Griffiths et al. 1998). of bDp to describe the approximate latitudes where Unless already banded, we banded all captured owls with those feathers were grown (Meehan et al. 2001, a uniquely-numbered aluminum leg band provided by Wassenaar and Hobson 2001, Kelly et al. 2002). the U.S. Geological Survey. Analyses of stable-hydrogen isotopes also have re- Reference Feathers. We collected reference feathers {N = 22) to calibrate the relationship between and vealed patterns of migratory movement in Neo- 8£y the bDp where the feathers were grown. We obtained tropical migratory birds (e.g., leap-frog chain and Flammulated Owl feathers from sites near Ogden, Utah, migration; Kelly et al. 2002, Smith et al. 2003). and Colorado Springs, Colorado, where collaborators col- We used stable-isotope analysis of Flammulated lected feathers from nestlings in 2002. Additional reference feathers came from collection managers at the Uni- Owl feathers to answer three specific questions. versity of New Mexico and the University of Arizona, who First, are the owls captured at the banding station provided us with feathers from study skins of hatch-year in the Manzano Mountains of local or regional or- plumage Flammulated Owls taken in north-central New March 2005 Origins of Fall-captured Flammulated Owls 21

Predicted

= o/oo) /V 2 ( 85 to -95

A/ = 10 (-60 to 70®/oo)

/V = 45 (-30 to -60 o/ao)

Manzano Mountains

Figure 1. Map of potential natal origins of hatch-year Flammulated Owls captured in the Manzano Mountains, New Mexico, in 2002. Predicted precipitation values were divided into three categories and mapped to show the potential locations where owls in those groups may have originated. See Methods for further description of map preparation.

Mexico and the Chiricahua Mountains in southeastern We calculated the isotope ratios of non-exchangeable Arizona. Collection dates of museum skins ranged from hydrogen in feather samples via comparative equilibra- 1959-95. These reference feathers cover much of the tion using keratin standards after Wassenaar and Hobson Fliimmulated Owl’s range in the Rocky Mountain States. (2003). The isotope ratios of non-exchangeable hydro- Laboratory Methods. We prepared feather samples by gen in keratin standards were determined using steam first cleaning them of oils with a chloroform-methanol equilibration methods (Wassenaar and Hobson 2000). (2:1) solution (Wassenaar and Hobson 2000) and then The keratin standards we used were black bear (Ursus air drying them for 14 d to enable exchangeable hydro- americanus) fur samples from Louisiana (non-exchange- = — — gen (13-22%) to equilibrate with laboratory-ambient able hydrogen bD 58%o) and Alaska ( 164%o). The moisture (Chamberlain et al. 1997, Wassenaar and Hob- comparative equilibration equation we used to convert son 2000). We then packed feather clippings (0.18-0.20 whole-sample values to non-exchangeable values was: mg) in silver capsules (3.5 X 5 mm; Costech, Valencia, ®7^nor>.exchangeable (8/V^hoie^pie + 29.89)/0.65 CA, U.S.A.), pyrolized the samples using a Finnigjan MAT TC-EA. elemental analyzer (Thermo Electron Corpora- We report both whole-sample and non-exchangeable hy- tion, Boston, MA U.S.A.), and analyzed sample hydrogen drogen-isotope ratios of reference and fall-collected using a Delta*’*"® XL mass spectrometer (Thermo Elec- feathers to facilitate comparison with other studies. tron Corporation, Boston, MA U.S.A.) in continuous flow Mappii^ Methods. We estimated the origins of owls mode at the University of New Mexico Stable Isotope captured in the Manzano Mountains by (1) calculating a Laboratory. We used the following standard model to cal- regression model for the relationship between hydrogen- culate whole-sample 8£> and report bD values in parts per isotope ratios in reference feathers and estimated grow- thousand (%o): ing season bDp for reference-feather collection sites, (2) using this regression to predict growing season bDp for bD = {(hydrogen-isotope ratio of sample) each feather sampled in the Manzano Mountains, and (hydrogen-isotope ratio of Vienna (3) using Geographic Information System (GIS) analysis to query growing season bDp Flammulated Owl geo- Standard Mean Oceanic Water graphic range, and North American biome maps to identify potential origins. [VSMOW]) - 1} X 1000. Estimated bDp values for the predictive regression and The precision of our analyses was bD ± 3%o (1 SD) based determination of origins were from the GIS-based model on repeated measurements of internal laboratory stan- of Meehan et al. (2004; http://biology.unm.edu/wolf/ dards. precipitationD.htm) . We digitized a geographic range 22 DeLong et al. VoL. 39, No. 1

Table 1. Stable-hydrogen-isotope ratios in feathers are presented for reference and fall-captured Flammulated Owls (8Ty) values [%o]). Fall-capture feathers were collected during 2002 in the Manzano Mountains, New Mexico. Utah and Colorado reference feathers were collected during summer 2002. New Mexico and Arizona reference feathers were collected from museum skins (1959—95).

bDf ± SD Wp ± SD Non-Exchangeable Whole-Sample Mean Mean Location Hydrogen Hydrogen N Latitude Longitude

Reference sites

Arizona -30%o -50%o 1 31.85 109.35 New Mexico -75 ± 9%o -79 ± 6%o 5 35.91 106.00 Colorado -89 ± 6%o -88 ± 4%o 6 39.11 105.04 Utah -98 ± 4%o -94 ± 3%o 10 41.32 111.58

Fall captures Manzano Mountains -52 ± 19%o -64 ± 12%o 57 34.70 106.40

map for Flammulated Owls from McCallum (1994) and Manzano Mountains using non-exchangeable 8Ty entered this into the GIS to limit bDp map queries to values and reference equation (1) . There would be geographic regions of North America where Flammulat- no difference in our results between using equa- ed Owls breed. We used a digitized map of North Amer- ican biomes from Reichenbacher et al. (1998) to limit tions (1) or (2), but we chose to proceed using ^Dp map queries to dry montane conifer forests, the bi- equation (1). selected Flammulated Owls (McCallum 1994). ome by Predicted bDp values were placed into three cat- Using the GIS, we selected bDp grid cells that fell within egories. Category one ranged from —30 to — 60%o range of predicted bDp values for birds captured at the = the banding station, and that occurred within both the {N 45), category two ranged from —60 to owl’s geographic range and associated biome type (Fig. — 70%o (N — 10), and category three ranged from these data should be viewed as a 1). We emphasize that —85 to — 95%o {N — 2). When mapped, the three spatial histogram rather than precise estimators of natal categories of predicted hDp displayed potential na- origins. tal origins of captured Flammulated Owls that Results ranged from the immediate local vicinity of the through the northwestern The mean values for non-exchangeable and banding station up U.S.A. Owls in the first category (with the least whole-sample hydrogen from owls at the four ref- negative bDp values) had potential origins in the erence sites ranged over 68 %o and were progres- isolated mountain ranges of west-central New Mex- sively more negative with increasing latitude (Table ico and east-central Arizona (Fig. 1). Hence, most 1). The mean 8/)^ value for captured owls in the Manzanos was between the mean values for south- owls could have been local or from neighboring ranges. in the second category had ern Arizona and northern New Mexico (Table 1). mountain Owls The relationship between 8Z)^ and reference potential natal origins estimated at the higher el- feather 8Tyfor non-exchangeable hydrogen — evations of mountain ranges near the Manzanos

0.47) was estimated as: and in northern New Mexico and southern Colo- rado. Two owls were placed in the third category 8Ty= 1.33(8Z)p + 16%o. (1) (with the most negative 8£y values) and had poten- The standard errors for the non-exchangeable tial origins in either the extreme high elevations slope and intercept were 0.13 and 25, respectively. of their breeding areas in northern New Mexico The relationship between 8Z)^ and bDj for whole- or in an area stretching from the Rocky Mountain sample hydrogen (/? = 0.48) was estimated as; front in Colorado up through northwestern states - such as Oregon and Washington. bDf= 0.87 (hDp) 19%o. (2) We captured most owls in September, with few The standard errors for the whole-sample slope owls captured after the first week of October. The and intercept were 0.20 and 16, respectively. We seasonal pattern of owl captures was not related to predicted a 8Z>^ value for each owl captured in the 8Ty values and, therefore, not likely related to the March 2005 Origins of Fall-captured Flammulated Owls 23

New Mexico, with many owls potentially originating in the immediate local vicinity of the banding

station (i.e., Manzano Mountains). It is most likely that owls in the second category originated in northern New Mexico and southern Colorado, given that this area represents the largest area of potential origin. However, the second category includes many areas close to the banding station, indicating that some owls in category two also are

from neighboring mountain ranges. If there is no directionality to the movements of Flammulated Owls during September, then many of the owls in categories one and two could have originated from throughout most of the montane areas of both New Mexico and Arizona. In the third category, there are two owls with isotope signatures that placed them anywhere in a large geographic area Figure 2. Relationship between stable-hydrogen-isotope the highest elevations in ratios of feathers (8-Dy) and Julian capture date for hatch- from New Mexico up year Flammulated Owls captured in the Manzano Moun- through Washington (Fig. la). tains, New Mexico, in 2002. These results are one of the first pieces of evidence that suggest southward migratory movements in Flammulated Owls. At least two owls likely origins of the owls (Fig. 2). However, the two owls originated north of New Mexico, making their in the third category were captured toward the end movement to the banding station consistent with of the banding season (mid-October; Fig. 2). It is what we would expect from migrating birds. As- possible that these owls were coming from further suming that the direction of long-distance move- north than the other owls, suggesting these two ments during the fall is to the south, then these owls were undertaking migratory movements when two owls made movements of at least 200 km (and captured. possibly much more) to arrive in the Manzanos. There was no difference in values (t = 0.35, Although our data provide new insights into the df = 31.8, P — 0.73) or Julian capture date between movements of Flammulated Owls in the Manzano males and females {t = 0.61, df = 39.8, P = 0.54). Mountains, our results are imprecise because of Hence, there were no sex-specific differences in several factors that limit our ability to use hydrogen the predicted origins or timing of captured owls. isotopes to determine the origins of particular birds. These factors are particularly difficult to Discussion overcome in the mountainous states of the south- Our results indicate that hatch-year Flammulat- western U.S.A. and the southern Rocky Mountains. ed Owls captured during fall in the Manzano First, the latitudinal gradient in isotope ratios al- Mountains represent a combination of local and lows only coarse predictions of potential origins regional birds, and a small number of migrants (Meehan et al. 2001). Second, the latitudinal gra- from the north (Fig. la). We divided our predicted dient in isotope ratios is complicated in the south- bDp into three categories and mapped the areas western U.S.A. due to proximity to the Pacific where those values could be found (Fig. 1). Using Ocean, the Gulf of California, and the Gulf of Mex- this approach, we offer three general statements ico (Dansgaard 1964). Finally, the latitudinal gra- about the potential origins of captured owls based dient is complicated by a negative relationship be- on the three mapped categories. In the first cate- tween elevation and isotope ratios (Poage and gory, we find owls that could have originated from Chamberlain 2001, Bowen and Wilkenson 2002). much of the montane areas in Arizona and New This latter relationship makes it difficult to distin-

Mexico (Fig. lb). There is no evidence that young guish potential source areas such as those at high Flammulated Owls make long-distance movements elevations in the south from those at lower eleva- to the east or west, so it is likely that the large ma- tions further north. Importantly, we used methods jority of captured individuals originated in central that accounted for the various processes determin- .

24 DeLong et al. VoL. 39, No. 1 ing isotope ratios in local rainfall by mapping a ever, we identified potential natal areas for relationship between 8£yvalues and estimated local captured owls that were primarily local and region- hDp values rather than assuming a simple latitudi- al. Indeed, every sampled owl could have originat- nal relationship over the western United States. ed in New Mexico (although the two potential mi- Despite the limitations, this stable-hydrogen-iso- grants would be from far northern New Mexico) tope analysis has produced a very useful picture of We do not believe that this finding is a failure of the natal origins of owls captured in the Manzano the method. Stable-hydrogen-isotope analysis of Mountains, a picture that would be difficult to bird feathers has been used successfully to describe compile using band recoveries of a small, noctur- source ranges for focal species at other migration nal bird. monitoring stations (Wassenaar and Hobson We also found no overall relationship between 2001). For example, a study on Sharp-shinned capture date and values (Fig. 2). The absence Hawks {Accipiter striatus) captured during migra- of a relationship to indicate migratory patterns tion at the Manzano Mountains study site, using such as whether northern or southern birds pass procedures identical to those used in this study, through the site first (Smith et al. 2003) may have confirmed that captured birds had originated resulted from the geographically-limited source across a wide latitude spanning New Mexico to population we sampled. There still may be inter- Alaska (Smith et al. 2003), similar to patterns in- esting migratory patterns to detect if owls can be dicated by long-term band-recovery data (Hoffman sampled from a larger portion of the range. The et al. 2002). two clearly southward-moving birds were captured Fall movements of young Flammulated Owls in mid-October, suggesting that October may be an in New Mexico remain somewhat of a mystery. important time for longer movements of young Whether Flammulated Owls captured during fall in Flammulated Owls in New Mexico. This result is the Manzano Mountains are local birds or dispers- consistent with other views on the timing of Flam- ers from other parts of New Mexico is still un- mulated Owl migration (McCallum 1994). How- known. Finally, answering the question of what ever, why we captured the bulk of the owls in Sep- type of migratory movements Flammulated Owls tember and so few owls in October, despite nets undertake may require considerably more effort. being open in late October, remains to be ex- Banding efforts that target potential wintering ar- plained. eas and other likely stopover locations (in partic- We found no gender-specific differences in cap- ular where Flammulated Owls do not breed) may ture timing. We investigated this possibility because shed light on this question, especially if used in many migrating raptors show gender-specific dif- combination with further isotopic analysis or ge- ferential migration timing (DeLong and Hoffman netic markers that can match wintering or migrat- 1999). Such differences could mask seasonal dif- ing birds to potential natal areas. ferences in the origin of captured birds because temporal separation of owls originating in the Acknowledgments same locations could make it difficult to accurately Primary financial support was provided by the USDA detect a relationship between owl origins and cap- Forest Service, Cibola National Forest and Region 3, and ture date. absence of a gender-specific timing The the New Mexico Game and Fish Department Share with difference reduces the possibility that we over- Wildlife Program. Additional funds for the project came looked a relationship between capture date and or- from Jeanie and Jodie Plumber. Beverly deGruyter at the Station, Smith igin. It is also likely that timing differences between Sandia Ranger and Howard Gross and Jeff at HawkWatch International were instrumental in ar- males and females were not yet developed because ranging funding and logistical support for this project. these owls likely originated relatively close to the Wendy King and Apple Snider conducted most of the Manzanos. fieldwork. Bob Dickerman (University of New Mexico), The breeding range of Flammulated Owls ex- Tom Huels (University of Arizona), Brian Linkhart (Col- tends north from the Manzano Mountains into orado College), and Diane McCabe (U.S. Forest Service, Colorado and Wyoming and further northwest into Ogden Ranger District) all provided juvenile Flammulat- ed Owl feathers from their study areas or their universi- Utah, Idaho, Montana, and Alberta, Canada ty’s study skin collections for use as isotope reference anticipated that cap- (McCallum 1994). We many samples. The New Mexico Coffee Company provided Av- tured owls would have clearly come from through- alon® organic, shade-grown coffee to keep field staff out the full latitudinal extent of their range; how- awake. Keith Hobson, Robert Rosenfield, Jeff Smith, and March 2005 Origins of Fall-captured Flammulated Owls 25

an anonymous reviewer provided helpful comments on in animal movement studies, hot. Environ. Health Stud this manuscript. 40:291-300.

, C.A. Lott, Z.D. Sharp, R.B, Smith, R.N. Rosen- Literature Cited field, A.C. Stewart, and R.K. Murphy. 2001. Using hydrogen isotope geochemistry to estimate the natal Able, K.P. 1999. Gatherings of angels: migrating birds latitudes of immature Cooper’s Hawks migrating and their ecology. Comstock Books, Ithaca, NYU.S.A. through the Florida Keys. Condor 103:11-20. Bowen, G. and B. Wilkinson. 2002. Spatial distribution , R.N. Rosenfield, V.N. Atudorei, J. Bielefeldt, of delta 0-18 in meteoric precipitation. Geology 30: LJ. Rosenfield, A.C. Stewart, W.E. Stout, and M.A. 315-318. Bozek. 2003. Variation in hydrogen stable-isotope ra- Chamberlain, C.P., Blum, R.T. Holmes, X. Feng, J.D. tios between adult and nestling Cooper’s Hawks. Con- T.W. Sherry, and G.R. Graves. 1997. The use of iso- dor 105:567-572. tope tracers for identifying populations of migratory Poage, M.A. and C.P. Chamberlain. 2001. Empirical re- birds. Oecologia 109:132-141. lationships between elevation and the stable isotope Dansgaard, W. 1964. Stable isotopes in precipitation. Tel- composition of precipitation and surface waters: Con- lus 16:436-468. siderations for studies of paleoelevation change. Am

DeLong, J.P. 2004. Age determination and preformative J. Science molt in hatch-year Flammulated Owls during the fall. Reichenbacher, F., S.E. Franson, and D.E. Brown. 1998 N. Am. Bird Bander North American biotic communities map. Univ. Utah and S.W. Hoffman. 1999. Differential autumn mi- Press, Salt Lake City, UT U.S.A. Reynolds, R.T. and B.D. gration of Sharp-shinned and Cooper’s hawks in west- Linkhart. 1987. The nesting biology of Flammulated in Colorado. Pages 239- ern North America. Condor 101:674-678. Owls 248 in R.W. Nero, R.J. Clark, R.J. Knapton, and R.H Griffiths, R., M.C. Double, K. Orr, and RJ.G. Dawson. Harare [Eds.], Biology and conservation of northern 1998. A DNA test to sex most birds. Mol. Ecol. 7:1071- forest owls. U.S.D.A. Forest Service General Technical 1075. Report RM-142, Rocky Mountain Forest and Range Hobson, K.A. and L.I. Wassenaar. 1997. Linking breed- Experiment Station, Fort Collins, CO U.S.A. ing and wintering grounds of neotropical migrant Smith, R.B., T.D. Meehan, and B.O. Wolf. 2003. Assess- songbirds using stable hydrogen isotopic analysis of ing migration patterns of Sharp-shinned Hawks Accip- feathers. Oecologia 109:142-148. iter striatus using stable-isotope and band encounter Hoffman, S.W., J.P. Smith, and T.D. Meehan. 2002. analyses. J. Avian Biol. 34:387-392. Breeding grounds, winter ranges, and migratory Wassenaar, L.I. and K.A. Hobson. 2000. Improved meth-

routes of raptors in the mountain West. J. Raptor Res. od for determining the stable-hydrogen isotopic com- 36:97-110. position (delta D) of complex organic materials of

Kelly, J.F., V. Atudorei, Z.D. Sharp, and D.M. Finch. environmental interest. Environ. Sci. Tech. 34:2354— 2002. Insights into Wilson’s Warbler migration from 2360. analyses of hydrogen stable-isotope ratios. Oecologia and . 2001. A stable-isotope approach to 130:216-221. delineate geographical catchment areas of avian migration monitoring stations in North America. Envi- McGallum, D.A. 1994. Flammulated Owl (Otus flammeo- ron. Sci. Tech. 35:1845-1850. lus). In A. Poole and F. Gill [Eds.], The birds of North and . 2003. Comparative equilibration and America, No. 93. The Birds of North America, Inc., online technique for determination of non-exchange- Philadelphia, PA U.S.A. able hydrogen of keratins for use in animal migration Meehan, T.D., J.T. Giermakowski, and P.M. Cryan. 2004. studies, hot. Environ. Health Stud. 39:211-217. GIS-based model of stable hydrogen isotope ratios in North American growing-season precipitation for use Received 29 January 2004; accepted 15 October 2004 / Raptor Res. 39(l):26-35 © 2005 The Raptor Research Foundation, Inc.

EFFECTS OF BREEDING EXPERIENCE ON NEST-SITE CHOICE AND THE REPRODUCTIVE PERFORMANCE OF TAWNY OWLS (STRIX ALUCO)

Lajos Sasvari^

Department of Zoology, Eszterhdzy Kdroly College of Education, H-3300 Eger, Lednyka u. 6, Hungary

ZoltAn Hegyi Management of Duna-Ipoly National Park, H-1 021 Budapest, Huvosvdlgyi ut 52, Hungary

Abstract.—Nest boxes for breeding Tawny Owls {Strix aluco) were located in a mixed oak-hornbeam- beech {Quercus—Carpinus—Fagus) forest located in the Duna-Ipoly National Park, 30 km northwest of Budapest, Hungary, during the period 1992-2004. We marked the parents individually in the first known breeding year of the females and recorded their reproductive performances through 5 subsequent breeding years. Reproductive performance of females increased with increasing breeding experience; they laid more eggs and reared more fledglings with subsequent breeding years. However, no significant differences were found in reproductive performance between the third and fifth breeding years. Fledg- ing success was higher when the males were older than the females, but hatching success was not influenced by the age of the males. Parents achieved higher hatching and fledging success in years without snow cover than those with snow cover. Fledging success was higher than hatching success in

the females’ first and second breeding years, but hatching success was higher in third, fourth, and fifth breeding years, which indicates age-dependent change in offspring production limitation by parents. Pairs changed nest sites and moved to lower altitudes in years with snow. As a consequence, the majority of older parents bred at low elevations. Based on the greater mass loss by females than males in adverse weather conditions, we concluded that males reduced the amount of prey brought to their mates to ensure their own survival in conditions in which food was scarce. Females raised lighter fledglings in snow years than in years without snow cover during their first and second breeding season, but the influence of snow cover on fledglings’ condition was not present in the broods of experienced parents.

Key Words: Tawny Owls; Strix aluco; fledging success; hatching success; parental age; parental condition; weather condition.

EFECTOS DE LA EXPERIENCIA REPRODUCTIVA SOBRE LA ELECCION DE SITIOS DE NIDIFI- CACION YEL DESEMPENO REPRODUCTfYO DE STRIX ALUCO

iiESUMEN. —Se instalaron cajas de nidificaddn para Strix aluco en un bosque mixto de Quercus, Carpinus, y Fagus localizado en el Parque Nacional Duna-Ipoly, 30 km al norte de Budapest, Hungria, entre 1992 y 2004. Marcamos individualmente a las parejas durante el primer ano reproductivo de las hembras y registramos su desempeno reproductivo durante los 5 anos siguientes. El desempeno reproductivo de las hembras aumento con el aumento de la experiencia reproductiva: estas pusieron mas huevos y criaron un mayor numero de polluelos en los anos posteriores. Sin embargo, no se encontraron diferencias significativas entre el cuarto y el quinto ano reproductivo. El exito de emplumamiento fue mayor cuando los machos fueron mas viejos que las hembras, pero el exito de eclosion no fue influenciado por la edad de los machos. Las parejas alcanzaron un mayor exito de eclosion y de emplumamiento en los anos sin cobertura de nieve que en los anos con cobertura de nieve. El exito de emplumamiento

fue mayor que el exito de eclosion durante el primer y segundo ano reproductivo de las hembras, pero el exito de eclosion fue mayor durante el tercer, cuarto y quinto ano reproductivo, lo que indica un cambio dependiente de la edad en la limitacion de la produccion de progenie por parte de los padres. En los anos con nieve, las parejas cambiaron de sitio de nidificacion y se desplazaron hacia sitios de menor altitud. Consecuentemente, la mayoria de los padres de mayor edad nidificaron en elevaciones bajas. Con base en la mayor perdida de peso en las hembras que en los machos en condiciones de

^ Email address: [email protected]

26 March 2005 Tawny Owi. Breeding Experience 27

clima adverse, concluimos que los machos redujeron la cantidad de presas llevadas a sus parejas para asegurar su propia sobrevivencia en condiciones en las cuales el alimento fue escaso. Durante el primer y segundo ano reproductive, las hembras criaron volantones de menor peso en los anos con nieve que en los anos sin nieve, pero la influencia de la cobertura de nieve sobre la condicion de los volantones no se observe en las nidadas de parejas experimentadas. [Traduccion del equipo editorial]

Both theoretical papers and empirical evidence both body mass and length of tarsus on nestlings indicate that young birds invest less in reproduc- before fledging. tion than do older birds (Williams 1966, Pianka On the basis of the sexual dimorphism in Tawny 1976), which may be due to the young birds’ poor- Owls, we hypothesized that the lighter male offer condition (Coulson 1968, Pugesek and Diem spring, which demand less parental investment, 1983, Weimerskirch 1992) or their inexperience in survive better than heavier female offspring during foraging and knowledge of the habitat (Orians food shortages (e.g., Olsen and Cockburn 1991, 1969, DeSteven 1978). Long-term studies on owls Wiebe and Bortolotti 1992, Dzus et al. 1996). If the have also shown the effects of age on breeding per- different sex offspring require varying amounts of formance (Recher and Recher 1969, Korpimaki care, the young that demands more parental effort 1988, Gehlbach 1989, Saurola 1989). We have should be fewer in a poor-food environment re- shown in a previous study the effect of age com- ducing the total reproductive cost to the parents position on breeding success of Tawny Owls {Strix (Slagsvold 1990, Glutton-Brock 1991, Weatherhead aluco) and found sex-related influences on number and Teather 1991). To examine the reduction of of eggs, hatching and fledging success in first, sec- reproductive cost by elimination of heavier off- ond, and third breeding years of the pairs (Sasvari spring, we related the body condition of nestlings and Hegyi 2002). The aim of our recent study was before fledging to the number of breeding seasons to examine age-dependent reproductive perfor- that females were present and to the weather. mance through five consecutive breeding years of Methods owl parents and the effect of weather both on We placed 220 nest boxes for breeding Tawny Owls in breeding success and nest-site choice of the pairs. a mixed oak-hornbeam-beech (Quercus— Carpinus—Fa- Southern Lowe suggested that prey and (1968) gus) forest, with 40-60-yr old trees, in the Duna-Ipoly Na- availability for Tawny Owls is determined by tional Park, 30 km northwest of Budapest (47°35'N; ground cover, and when snow prevents them prey- 19°02'E) during the period 1992-2004. Six to eight nest boxes were grouped together with 300-600 between ing on small mammals, they switch to hunting m them, the groups being separated by 2-5 km. Nest boxes mainly birds. Many papers have reported that were checked at 4—8 d intervals beginning at the end of throughout Europe, this species relies mostly on January. rodents, but will feed on birds as a secondary, al- We captured 157 females and 141 males during the nestling period by placing a net over the entrance of the ternative food (Southern and Lowe 1968, Gosz- boxes while the birds were inside. The birds were marked ezynski 1981, Mikkola 1983, Kirk 1992,Jedrzejewski with different combinations of colored rings for individ- et al. 1994). We thus examined the breeding per- ual identification. We identified 44 females that bred formance achieved by the pairs in snow years and through three successive breeding seasons and 26 females that bred through four seasons, 17 females in years when snow did not cover the ground dur- and that bred through five seasons. Owls changed mates on ing the incubation and early nestling periods. In nine occasions, but none lost their nests through preda- addition, we recorded the distribution of nest sites tion. Age of females was determined by the pattern of at different elevations and changes in nest-site the primaries and secondaries (Petty 1992) in their first choice depending on snow condition. known breeding year and their mates were categorized as (1) of same age or younger, or (2) older. The 44 fe- The Tawny Owl is a resident, strongly monoga- males in their first known breeding year consisted of 15 mous owl in central Europe that can be attracted 1-yr old, 23 2-yr old, and six 3-yr old birds. Body mass of to artificial nest boxes. We marked individual par- parents were measured when their first hatched-young ents and determined the age (Petty 1992) of the were 3 d old, and fledgling masses were recorded when they were 25-28 d old. pairs in the first known breeding years of the fe- As a consequence of the 550 m altitude range of the males. In order to evaluate the condition of the study area (130-680 m), snow covered the ground longer owls, we measured the body mass of parents and in the higher-elevational nest areas than the lower ones. 28 Sasvari and Hegyi VoL. 39, No. 1

Table 1. Mean reproductive performance measures (±SD) of female Tawny Owls over five successive breeding seasons in relation to the age of their mates and snow condition around the nest. Numbers in parentheses indicate number of females.

Breeding Snow Cover Years of Age of Males ON THE Number Hatching Fledging Number of Females Reiated to Females Ground OF Eggs Success Success Fledglings

First Younger or same Yes (9) 2.22 -h 0.72 0.65 0.12 0.85 + 0.04 1.22 ± 0.60 -+ No (15) 2.33 0.87 0.71 ± 0.10 0.92 0.03 1.53 ± 0.38

Older Yes (7) 2.00 1.00 0.64 H- 0.08 0.88 ± 0.05 1.14 ± 0.48 No (13) 2.54 “h 0.97 0.73 -h 0.07 0.92 -t- 0.04 1.69 ± 0.60 H- Second Younger or same Yes (7) 2.14 0.48 0.67 0.11 0.90 ± 0.05 1.29 ± 0.49 No (16) 2.81 + 1.07 0.77 + 0.07 0.91 0.04 2.00 ± 0.71 Older Yes (9) 2.33 0.75 0.71 + 0.03 0.93 0.08 1.56 ± 0.62 No (12) 2.92 0.73 0.78 0.04 0.93 0.02 2.08 ± 0.73 Third Younger or same Yes (10) 2.90 1.06 0.90 + 0.04 0.73 H- 0.06 1.90 ± 0.77 No (14) 3.00 -H 0.69 0.93 H- 0.05 0.77 -h 0.03 2.44 ± 0.74

A year when snow completely covered the ground for a the effects of snow on clutch size and hatching suc- radius of 1 km from the owl nest during the incubation cess. However, broods of older males experienced and early nestling period (until 10 d after hatching of the last young) was considered as a snow breeding year higher fledging success and produced more nest- for any given pair. The elevations between 130-680 m lings both in snow years and in years without snow were separated into three categories: <300 m, 300-500 cover. m, and >500 m, which included 64, 85, and 71 nest box- Females laid more eggs and fledged more nest- es for the owls, respectively. The number of nests occupied by the pairs in each of the three altitudinal ranges lings as they aged (combined data on age of males, = was related to the number of breeding years of the fe- ANOVA: ^4 170 = 3.77, P 0.005; F4170 = 5.31, P males and condition of the given year. snow < 0.001; respectively), but there were no signifi- Statistical analyses were carried out using the SPSS sta- cant differences in reproductive performances of tistical package (Norusis 1977). Hatching success and fledging success were calculated by number of eggs females between their third and fifth breeding sea-

hatched per number of eggs laid and number of nest- sons (^2,84 = 2.97, P = 0.063; ^2,84 - 3.07, P < lings fledged per number of nestlings hatched, respec- 0.072) . Hatching success was not influenced by the tively. Percent data were arcsine transformed for para- age of male related to female age = 3.16, P metric analysis. (ffi J73 = 0.077); however, fledging success was higher

Results when the males were older than the females (Fj 173 = Reproductive Performance. We found no signif- 9.17, P < 0.001; respectively). Parents achieved icant relationships between the breeding year of both higher hatching success and fledging success the female and male age for number of eggs and in years without snow cover than those with snow hatching success, but in all breeding years, broods cover during the incubation and early nestling pe- with older males than the females experienced riod (ifi 173 = 8.96, P < 0.001; fy 473 = 9.03, P < higher fledging success (Tables 1, 2). Snow con- 0.001; respectively). Higher fledging success than ditions affected all categories of reproductive per- hatching success was recorded in first and second — formance of females. Male age did not influence breeding years of the females 42 = 8.94, P March 2005 Tawny Owl Breeding Experience 29

Table 2. Three-way ANOVA for the relationship between reproductive performance of female Tawny Owls and breeding years, age of males, and snow effects. Categories for the variations: first, second, third, fourth, and fifth known breeding season of females; males of the same age or younger males than their mates, compared with males older than their mates; snow cover versus no snow cover during the incubation and early nesting period. N = 131 females.

Source of Variation Response Variart.es df F P

Breeding years of females X age of males Number of eggs 4 2.28 0.074 Hatching failure 4 2.17 0.081 Nestling mortality 4 2.87 0.027 Number of fledglings 4 2.73 0.034 Breeding years of females X snow Number of eggs 4 3.87 0.006 Hatching failure 4 4.62 0.003 Nestling mortality 4 4.97 <0.001 Number of fledglings 4 5.12 <0.001 Age of males X snow Number of eggs 1 2.94 0.084 Hatching failure 1 3.43 0.069

Nestling mortality 1 6.97 0.003

Number of fledglings 1 4.80 0.029 Breeding years of females X age of males X snow Number of eggs 4 2.57 0.043 Hatching failure 4 3.01 0.022 Nestling mortality 4 4.61 0.002 Number of fledglings 4 3.79 0.007

0.003; 42 = 9.37, P < 0.001; respectively), but between the females and males are presented as hatching success exceeded fledging success in the percentage mass loss in snow years in relation to third, fourth, and fifth breeding years of the fe- mass in years without snow cover, the smaller de- males (ifi 42 = 11.52, P< 0.001; Ti 24 = 11.20, P< crease for males than females is notable (Fig. 2). = 0.001; and 15 = 8.92, P 0.002) . Between-year Shift in Nest Sites. Distribution of Body Mass. Body mass of both females and selected nest sites between the three altitude rang- males increased as the number of breeding years es showed significant differences for the five suc- increased (female: = — = T4 i 7o 2.93, P 0.021, male: cessive breeding seasons of the females (x^g 7^4,170 ~ 3.10, P < 0.017; Fig. 1) but there were no 24.72, P < 0.01; Fig, 3). In the first and second significant differences in body mass between the breeding years, nest sites were chosen mainly be- third fifth and breeding seasons (female: i^2 ,s 4 ~ tween 300-500 m elevation, and a high proportion 2.52, P = 0.087, male: = 2.69, P - 0.073). of the owls nested above the 500 m, but in third, Female body mass was lower in years with snow fourth, and fifth breeding seasons the majority of than in years without snow cover in the first, sec- the females nested below 300 m. The increase in ond, and third breeding seasons, although the P the proportion of breeders in the lowest altitude values declined from the first to the third breeding range was greatest between second and third years (^3 = 4.52, P < 0.001; ^43 = 3.47, P < 0.01; breeding years of the females, and the highest pro- %3 = 2.40, P < 0.05; respectively) and there was no portion was recorded in fourth breeding season significant difference in fourth and fifth breeding (X^g - 24.38, P< 0.001). — year (% = 1.47, NS and t^Q 1.30, P > 0.005). A The movement between the altitude ranges was similar tendency was recorded for male body mass, related to snow conditions and the age of breeding but the differences were lower than those of fe- females (Table 3). A large number of females males in first and second breeding years (^43 = changed elevation in their second breeding year in

2.62, P < 0.02; ^43 2.28, P < 0.05; respectively) relation to the previous breeding season, but only and disappeared in third, fourth, and fifth breed- a few females did so if there was no snow cover in ing seasons = = — (^43 = 1.44, % 1.16, fie 1.30, re- the early breeding season (x^i 6.31, P < 0.02). spectively; P> 0.05). If the differences in mass loss Movement of females between the three altitude 30 Sasvari and Hegyi VoL. 39, No. 1

16 28 16 28 18 26 11 15 9 8 550 - 525 - aj) 500 - (L> 475 I £ 450 ^425 I 400 375 350

Breeding Years of Female Tawny Owls

Figure 1. Body mass of Tawny Owl parents in five successive breeding years when snow covered and did not cover the ground during the incubation and early nestling period. Open bars indicate masses in snow years and black bars indicate masses in years without snow cover. Error lines indicate SD. Numbers above the bars indicate number of parents.

— = ranges was also found to be more common in snow dition (£13 1.59, ^5 = 2.17, £ig 1.19; P> 0.05 years in their third breeding season (xî = 4.08, P in all occasions). < 0.05). However, snow conditions did not influence changes between elevations in the fourth and Discussion fifth breeding years = 0.13 and = 0.15, (xî xî Hatching Success Versus Fledging Success. The respectively; P > 0.05). In most cases females relatively low fecundity of young females compared moved from higher to lower elevations (25 of 35 to older females has been documented both in pas- changes; 71.4%, xS = 12.91, P< 0.001). serines (Perrins 1979, Dhondt 1989) and non-pas- Body Mass and Length of Tarsus before Fledg- serines (Newton 1989, Saether 1990, Sydeman et ing. Mean body mass and mean tarsal length per al. 1991). Thus, the small clutch size with low brood of the nestlings before fledging increased in hatching success of Tawny Owl females may also be subsequent breeding years = 3.69, P — due to low fecundity in their first and second 0.005; /q 170 — 2.87, P — 0.021; respectively; Fig. 4), breeding years. Male owls feed their mates during but differences were not recorded between the the incubation period, but egg survival was not in- third and fifth breeding seasons (F2 84 = 3.01, P = fluenced by male age. Nevertheless, in the females’ 0.069 and F284 = 3.09, P — 0.062; respectively). first breeding years the reduction in Nestlings were heavier with longer tarsal length in and second years without snow cover than in snow years in the number of offspring occurred in the incubation period rather than the nestling period because females’ first (^43 = 2.46, P< 0.02; ^43 = 3.88, P< fledgling success was higher than hatching success. 0.001; respectively) and second breeding years (^43 For birds with breeding experience, during — 2.33, P < 0.05; ^43 — 4.04, P < 0.001; respec- more tively). In the females’ third, fourth, and fifth their third, fourth, and fifth breeding years, the breeding years, nestlings did not differ either in relationship between hatching success and fledg- body mass or tarsal length according to snow con- ing success was reversed: lower fledging success March 2005 Tawny Owl Breeding Experience 31

(44) (44) (44) (26) (17)

Number of Breeding Years

Figure 2. Percent mass loss in snow years related to body mass recorded in years without snow cover in female and male Tawny Owls in five successive breeding years. Solid line and broken line indicate percent mass loss of females and males, respectively. Mass losses were calculated using body mass recorded in snow years and in years without snow cover. Numbers above indicate the number of females and males.

Breeding Years of Female Tawny Owls

Figure 3. Percentage distribution of nest sites among the three altitude ranges in five successive breeding seasons of female Tawny Owls. The number of nests are presented above the bars. 32 Sasvari and Hegyi VoL. 39, No. 1

Table 3. Percentage distribution of females that Compared to pairs where the males were the same changed or retained nest sites between the three altitude age or younger than their mates, pairs where the ranges (<300 m, 300-500 m, >500 m) in relation to males were older than the females raised more off- snow cover and successive breeding seasons. The changes spring with higher fledging success. and retentions are related to the nest sites in previous Longitudinal studies on bird species have shown breeding season. The number of pairs are presented in that clutch size and fledging success increased with parentheses. age to a plateau and decreased among the oldest breeders (Newton et al. 1983, Thomas 1983, Nisbet Breeding et al. 1984, Newton 1989, Pugesek and Wood Year of Snow Nest Site Nest Site Females Cover Changed Retained 1992). We have not yet conducted the prolonged studies of the Tawny Owl that would allow us to Second Yes 43.8 53.3 (7) (9) examine the possible effects of senescence. Nev- No 10.7 (3) 89.3 (25) ertheless, we believe that the present study was Third Yes 61.1 (11) 38.9 (7) long enough to demonstrate that the females No 19.2 (5) 80.8 (21) reached a plateau in their breeding success, be- Fourth Yes 18.2 (2) 81.8 (9) No 13.3 (2) 86.7 (13) cause females showed no differences in reproduc- Fifth Yes 33.3 (3) 66.7 (6) tive performances after their third breeding years. No 25.0 (2) 75.0 (6) Numerical Responses of Tawny Owls to Snow Cover. Predators may respond to fluctuations in the abundance of prey in different ways (Solomon limited the number of offspring produced rather 1949). Numerical responses involve changes in re- than hatching success. productive success, survival, and immigration/ em- Both females and nestlings depend upon food igration rate, whereas functional responses reflect supplied by the males during the brooding period, changes in prey composition (Andersson and Er- thus the differences in fledging success and num- linge 1977). Long-term studies on nocturnal rap- ber of fledglings probably reflected male age. tors have shown both numerical and functional re-

Breeding Years of Female Tawny Owls

Figure 4. Mean body mass and length of tarsus of Tawny Owl nestlings per brood before fledging in five breeding years with and without snow cover during the incubation and early nestling period. Open and black bars indicate mass and length of tarsus in snow years and in years without snow cover, respectively. Error lines indicate SD. Numbers above the columns indicate number of broods. March 2005 Tawny Owl Breeding Experience 33 sponses to fluctuations in prey abundance, both in of moving, in terms of their increased reproductive boreal and temperate regions in northern latitudes performance, is due to the higher frequency of sec- (Southern and Lowe 1868, Adamcik et al. 1978, ondary prey available at lower elevations during ad-

1979, Korpimaki 1986, 1987, Pietiainen et al. 1986, verse-weather periods. Korpimaki and Norrdahl 1991). The reproductive In our previous study on the effect of Tawny performance of Tawny Owls increased with increas- Owls’ predation on songbirds (Sasvari and Hegyi ing breeding experience, but the change in pro- 1997)1998), we estimated the abundance of birds ductivity also reflected numerical responses of owls around the owl nests in snow years (1993 and to snow cover. 1996) and in years without snow cover (1995 and

We found that even pairs with considerable . We recorded number of birds over a period breeding experience achieved lower reproductive of 30 min in a radius of 150—200 m of the nests success in adverse weather conditions with snow during the incubation period. The surveys were cover. Analysis of diet showed that, when the avail- carried at low, middle, and high altitude ranges ability of small mammals was low because of snow between 130—680 m at 24, 31, and 29 sites in snow cover, the males delivered more birds to females years and 33, 38 and 32 sites in years without snow and their offspring (Sasvari et al. 2000), and older cover. The mean number of birds recorded from males were better than young males at providing the low to high altitude range was 15.3 ± 8.7, 9.5 alternative prey. However, we suggest that in snow ± 7.6, and 3.4 ± 3.2 = 5.91, P = 0.004) in years both the young and old males delivered fewer snow years, and 13.6 ± 6.0, 11.7 ± 5.1, and 8.6 ± food items with lower total food mass than in years 4.7 (E’gaoo ~ 3.86, P — 0.027) in years without snow without snow cover and neither the inexperienced cover. These data show that possible prey species nor experienced males were able to compensate of birds were most abundant at low elevations in fully for the loss of the primary prey. We found all years, but their numbers were highest at the lower fledging success in snow years than in years lowest altitude range in years with snow, when without snow cover even in fourth and fifth breed- numbers were noticeably reduced at the highest ing seasons of the parents. altitude range. Higher Mass Loss for Females than Males in The birds, both the prey and predators, were Years with Snow Cover. When the snow effects re- more protected from the effect of adverse weather sulted in a change in prey availability, inexperi- in valleys than on the steep slopes of the hills. Also, enced parents suffered not only a greater reduc- villages and other man-made objects are found in tion in breeding performance, but also a larger valleys and the birds may also be able to find food decline in body condition. Reflecting the depen- related from human activity to aid winter survival. dence of the females on food supplied by the Lower Body Mass and Tarsal Length and Differ- males during the incubation and brooding period, ential Gender Surviv2il. In terms of sexual dimor- the differences in the mass between the snow years phism in raptors, dimorphism in size and body and years without snow cover were considerably mass is nearly as pronounced at the time of fledg- higher for females than males. Hence, we suggest ing, as in adulthood (Newton and Marquiss 1979, that male owls reduce prey provided to their mates Fiala 1981, Richter 1983, Bortolotti 1986). Adult during incubation and early nestling period to en- female Tawny Owls were heavier and larger than sure their own survival. In successive breeding the adult males, hence the differences in body years increased breeding experience meant that mass and tarsal length measured on nestlings, be- the males were better equipped to exploit the sec- fore fledging, reflected the sexual dimorphism of ondary food resources in adverse weather condi- offspring. If one sex requires more food than the tions and did not suffer loss of mass. other, this sex should experience increased mor- Nest Site Switching by Experienced Breeding tality when food resources are scarce, skewing the Pairs. The Tawny Owl parents shifted nest sites and sex ratio toward the less costly sex (Slagsvold 1990, relocated to new breeding territories at lower ele- Weatherhead and Teather 1991, Glutton-Brock vations in snow years. As a consequence of these 1991). We did not identify the sex of the owlets, changes, the majority of parents in their third but on the basis of body mass and tarsal length, we breeding season and following years nested at low presumed that the sex ratio in the broods of Tawny elevations. We suggest that leaving the higher ele- Owls was biased in favor of the “cheaper” male vations and the apparent benefit for older parents during difficult feeding conditions. 34 Sasvari and Hegyi VoL. 39, No. 1

The lower mean body mass and mean shorter Newton, [Ed.], Lifetime reproduction in birds. Aca- tarsi of the nestlings in a brood raised in snow demic Press, London, U.K. CoszczYNSKi, 1981. Comparative analysis of food of years may be due to the shortage of food and the J. owls in agrocenosis. Ekol. Pol. 29:431-439. better survival of the sex requiring less investment. Jedrzejewski, W., B. Jedrzejewska, K. Zub, A.I. Ruprecht, Nevertheless, we found no differences in body AND C. Bvstrowski. 1994. Resource use by Tawny Owls mass and length of tarsus of nestlings before fledg- Strix aluco in relation to rodent fluctuation in Bialow- ing related to cover in the third, fourth, and snow ieza National Park, Poland./. Avian Biol. 25:308-318 fifth breeding seasons. The condition of fledglings Kirk, D.A. 1992. Diet changes in breeding Tawny Owls raised in these years did not differ between the {Strix aluco). J. Raptor Res. 26:239-242. successive seasons. The influence of snow cover on KorpimAki, E. 1986. Gradients in population fluctuation fledglings’ condition was not apparent in the of Tengmalm’s Owl Aegolius funereus in Europe. Oec- broods of experienced parents. ologia {Berlin) 69:195—201.

. 1987. Dietary shifts, niche relationships, and re- Acknowledgments productive output of coexisting kestrels and Long-

We are indebted to Fred Gehlbach and anonymous ref- eared Owls. Oecologia {Berlin) 74:277-285. erees for their constructive comments and suggestions. . 1988. Effects of age on breeding performance of We are grateful to Susan Totterdell, Department of Phar- Tengmalm’s Owl Aegolius funereus in western Finland. macology, University of Oxford, for her linguistic correc- Omis Scand. 19:21-26. the of Zo- tions. This work was supported by Department AND K. Norrdahl. 1991. Numerical and function- ology, Eszterhazy Karoly College of Education, Eger, and al responses of kestrels, Short-eared Owls, and Long- Hungarian National Foundation for Scientific Research eared Owls to vole densities. Ecology 72:814-826. (project number: T 37388). We are also grateful to the Mikkola, H. 1983. Owls of Europe. Poyser, Staffordshire, Frank M. Chapman Memorial Fund of the American Mu- U.K. seum of Natural History, for its financial support. Newton, I. 1989: Lifetime reproduction in birds. Aca- Literature Cited demic Press, London, U.K.

Adamcik, R.S., A.W. Todd, and L.B. Keith. 1978. De- AND M. Marquiss. 1979. Sex ratio among nest- mographic and dietary responses of Creat Horned lings of the European Sparrow Hawk. Am. Nat. 113' Owls during a snowshoe hare cycle. Can. Field-Nat. 92; 309-315.

, AND P. Rothery. 1983. Age structure and 156-166. , survival in a sparrowhawk population. Anim. Ecol. , and . 1979. Demographic and di- J. , etary responses of Red-tailed Hawks during a snow- 52:591-602. shoe hare fluctuation. Can. Field-Nat. 93:15-27. Nisbet, I.C., J.M. WiNCHELL, AND A.E. Heise, 1984. Influ- breeding biology of Andersson, M. and S. Erlinge. 1977. Influence of pre- ence of age on the Common dation on rodent populations. Oikos 29:591—597. Terns. Colon. Waterbirds. 7:117-126. Bortolotti, C.R. 1986. Influence of sibling competition Norusis, M.J. 1977. SPSS/PC + advanced statistics 4.0. on nestling sex ratios of sexually dimorphic birds. Am. SPSS, Gorinchem, U.K. Nat. 127:495-507. Olsen, P.D. and A. Cockburn. 1991. Female-biased sex Clutton-Brock, T.H. 1991. The evolution of parental allocation in Peregrine Falcons and other raptors. Be- care. Princeton Univ. Press, Princeton, NJ U.S.A. hav. Ecol. Sociobiol. 28:417-423. Orians, 1969. and hunting success in the CouLSON, J.C. 1968. Differences in the quality of birds G.H. Age 17’ nesting in the centre and on the edges of a colony. Brown Pelican {Pelecanus occidentalis) . Anim. Behav. Nature 217:478-479. 316-319. DeSteven, D. 1978. Clutch size, breeding success, and Perrins, C.M. 1979. British tits. Collins, London, U.K.

parental survival in the Tree Sparrow {Iridoprocne bi- Petty, S.J. 1992. A guide to age determination of Tawny

color). Evolution 34:278-291, Owl Strix aluco. Pages 89-91 in C.A. Galbraicht, J.R Dzus, E.H., C.R. Bortolotti, and J.M. Cerrard. 1996. Taylor, and S. Perceival [Eds.], The ecology and con- Does sex-biased hatching order in Bald Eagles vary servation of European owls. Joint Nature Conserva- with food resources? Ecosdence 3:252-258. tion Committee, Peterborough, U.K. Dhondt, A.A. 1989. The effect of old age on the repro- PlANKA, E.R. 1976. Natural selection of optimal reproduction of Creat Tits Parus major and Blue Tits P. ca- duction tactics. Am. Zool. 16:775-784.

eruleus. Ibis 131:268-280. PiETiAiNEN, H., P. Sauroia, AND R.A. Valsanen. 1986. Pa- Eiala, K.L. 1981. Reproductive costs and the sex ratio in rental investment in clutch size and egg size in the Red-winged Blackbirds. Pages 198—214 in R.D. Alex- Ural Owl Strix uralensis. Ornis Scand. 17:309-325. ander and D.W. Tinkle [Eds.], Natural selection and PuGESEK, B.H. AND K.L. DiEM. 1983. A multivariate study social behavior. Chiron Press, New York, NY U.S.A. of the relationship of parental age to reproductive

Cehlbach, F.R. 1989. Screech-Owl. Pages 315—326 in I. success in California Gulls. Ecology 64:829-839. March 2005 Tawny Owl Breeding Experience 35

AND P. Wood, 1992. Alternative reproductive Solomon, M.E. 1949. The natural control of animal pop- strategies in the California Gull. Evol. Ecol. 6:279- 295. ulation./. Anim. Ecol. 18:1-35.

Recher, H.F. and J.A. Recher. 1969. Comparative forag- Southern, H.N. and V.P.W. Lowe. 1968. The pattern of ing efficiency of adult and immature Little Blue Her- distribution of prey and predation in Tawny Owl ter- ons {Elorida caerulea). Anim. Behav. 17:320-322. ritories. /. Anim. Ecol. 37:75—97. Sydeman, Penniman, T.M. Penniman, P. Pyle, Richter, W. 1983. Balanced sex ratios in dimorphic al- W.J., J.F. AND D.G. Ainley. 1991. Breeding performance in the tricial birds: the contribution of sex-specific growth Western Gull: effects of parental age, timing of breed- dynamics. Am. Nat. 121:158-171. ing and year in relation to food availability. Amm Saether, B.E. 1990. Age-specific variation in reproductive J. Ecol. 60:135-149. performance of birds. Current Ornithology 7:251-283. Thomas, C.S. 1983. The relationship between breeding Sasvari, L. and Z. Hegvi. 1998. Bird predation by Tawny experience, egg volume, and reproductive success of Owls (Strix aluco L.) and its effect on the reproductive the Kittiwake Rissa tridactyla. Ibis 125:567—574. performance of tits. Acta Oecol. 19:483-490. Weatherhead, P.J. and K.L.Teather. 1991. Are skewed

and . 2002. Effects of age composition of fledgling sex-ratios in sexually dimorphic birds adap- pairs and weather condition on the breeding perfor- tive? Am. Nat. 138:1159-1172. mance of Tawny Owls, Strix aluco. Folia Tool. 51:113— Weimerskirch, H. 1992. Reproductive effort in long-lived

120 . birds: age specific patterns of condition, reproduction

, and survival in the Wandering Albatross. Oikos 64: , T. CsoRGO, and L Hahn. 2000. Age-re- 464-473. lated diet change, parental care, and reproductive Wiebe, K.L. and G.R. Bortolotti. 1992. Facultative sex cost in Tawny Owls Strix aluco L. Acta Oecol. 21:267- ratio manipulation in American Kestrels. Behav. Ecol. 275. Sociobiol. 30:379—386. Saurola, P. 1989. Ural Owl. Pages 327-345 in I. Newton Williams, G.C. 1966. Natural selection, the cost of repro- [Ed.], Lifetime reproduction in birds. Academic duction, and a refinement of Lack’s Principle. Am. Press, London, U.K. Nat. 100:687-690. Slagsvold, T. 1990. Fisher’s sex-ratio theory may explain hatching patterns in birds. Evolution 44:1009-1017. Received 12 February 2004; accepted 5 December 2004 .

THE STATUS OF DIURNAL BIRDS OF PREY IN TURKEY

Levent Turan^ Hacettepe University, Faculty of Education, Department of Biology Education, 06532 Beytepe, Ankara, Turkey

Abstract.—Here, I summarize the current status of diurnal birds of prey in Turkey. This review was based on field surveys conducted in 2001 and 2002, and a literature review. I completed 661 field surveys

in different regions of Turkey in 2001 and 2002. I recorded 37 species of diurnal raptors, among the 40 species known in the country. In addition, some adverse factors such as habitat loss, poisoning, killing, capturing or disturbing raptors, and damaging their eggs were seen during observations.

Key Words: Eastern Europe, population status', threats', Turkey.

ESTATUS DE LAS AVES DE PRESA DIURNAS EN TURQUIA

Resumen.—^Aqm resumo el estatus actual de las aves de presa diurnas en Turquia. Esta revision esta basada en muestreos de campo conducidos en 2001 y 2002, y en una revision de la literatura. Complete 661 muestreos de campo en diferentes regiones de Turquia en 2001 y 2002. Registre 37 especies de rapaces diurnas del total de 40 especies conocidas para el pais. Ademas, registre algunos factores ad-

versos como perdida de habitat, envenenamiento, matanzas, captura o disturbio de rapaces y dano de sus huevos durante las observaciones. [Traduccion del equipo editorial]

Turkey, with approximately 454 bird species, has servations of diurnal raptors collected during a relatively rich avian diversity in Europe. Despite 2001-02 from locations throughout Turkey. recognized importance of the country in support- Methods ing a significant biodiversity, mapping of the avifauna has not occurred and there are few data on Turkey is divided into seven geographical regions (Eig. Erol et al. 1982) characterized by variable landscape the status of birds in Turkey. 1; types, climate differences, and a rich diversity of fauna the birds of Turkey are included 40 di- Among Field data were obtained from surveys conducted in all urnal birds of prey and 10 owls. For Europe and areas of Turkey between 1 January 2001-31 December the Middle East, Forsman (1998) lists 42 raptors, 2002. Many observations were based on a combination of the field surveys and data from birdwatchers and oth- Glutz et al. (1987) list 41, and Gensbol (1986) lists ers (Toygar 2001, 2002). The remaining observations 46 species. Weick and Kiziroglu et al. (1980) were gathered from the trip reports of visiting ornithol- (1993) reported 39 diurnal raptors in Turkey. This ogists in Turkey (Balmer and Betton 2001, Comas et al. was increased to 40 with the addition of the Bar- 2001, Dyczkowski 2001, Merril 2001, Swann 2001, Balmer and Betton 2002, Eriksen and Eriksen 2002, Giannatos, bary Falcon (Falco pelegrinoides; Kirwan et al. 1998) 2002, Klim 2002). However, the number of the studies on raptors in The methodology used was derived from standardized their Turkey is minimal and little is known about bird-survey techniques (Bibby et al. 1998), and from tran- distribution. Kumerloeve (1970) provided the first sect counts (Bibby et al. 2000). Daily surveys were con- significant contribution on the status and distri- ducted in the middle of the day from 0900-1300 H at 134 selected localities within 43 of 81 provinces in 2001, bution of raptors in Turkey. The initial focus of and 197 localities within 54 provinces in 2002. Observa- research raptors in Turkey was migration. Al- on tion grids were used to evaluate all observations and rec- though the number of studies in eastern Europe ords (Fig. 1; Appendix). examining birds have increased recently, there are During the observations, 162 line transects were used to assess nonbreeding raptor populations over extensive still little data and information available on the size areas. The mean distance of transects was 5098 m. Most of raptor populations and their conservation. of the observations were made by teams of one to three Here, I present a summary of species-specific ob- observers, often one person to verify identification and one person to record data. Also, 499 spot counts were made and evaluated to assess the populations of some ^ Email address: [email protected] raptor species. The mean spot counts per survey was 1.47.

36 March 2005 Status of Diurnal Raptors in Turkey 37

4 5 6 7 8 9 10 11 1 2 3 12 13 U 15 16 17 18 19

Spot counts were conducted during selected stops at lo- bul (Marmara region) on 2001. It was also seen 15 cations with a good view. A single observer systematically times during surveys between April-November scanned the sky for 5 min and counted all raptors visible with the naked eye. The coordinates of spot counts were 2002, but none were recorded in July. recorded with a Global Positioning Receiver System and Black Kite {Milvus migrans). This resident raptor binoculars were used to aid in the identification of the species was seen on 16 surveys, during all the species. months of 2001 with the exception of February. Definitions used to describe the status of birds in Tur- unexpected key are as follows (Weaver 1981, Kiziroglu 1989): One observation occurred in southeast Anatolia (Gaziantep Province), registered in Resident A bird that is present all year and breeds regu- December and involved 400 individuals (Demircan larly. Summer visitor. A bird that uses a particular area for breed- 2001). In 2002, Black Kite was observed 17 times ing only and is not present outside the breeding season. between April-September, with no records noted Winter visitor. A bird that visits a particular area only dur- in July. According to Clark (1999) Black Kites are ing the winter and does not occur there during its breeding period. local summer breeders throughout most of Eu- Migrant A bird that occurs irregularly and may be seen rope. Most Black Kites leave Europe for winter, but on migration, sometimes in great numbers. some stay in Turkey and in the Middle East. Vagrant A bird for which there are only one or a few White-tailed Eagle {Haliaeetus albicilla). Fairly com- records a year in Turkey. mon resident and winter visitor, the White-tailed Results and Discussion Eagle was recorded five times during 5 mo in 2001 and eight times in January, April, May, and Decem- Assistants and I recorded diurnal raptors at 134 ber in 2002. White-tailed Eagles in Turkey are from sites during 324 observation periods in the year the southeastern European population. The indi- 2001, and 197 sites during 416 observations in the year 2002. The data collected during 2001 and viduals of this population were smaller and have 2002 were compatible with each other to a great lighter-colored heads. They mostly reside in Cau- extent in terms of effort and number of raptors casus, Greece, and in parts of Bulgaria. In Turkey, recorded. Observations of the individual species this species generally lives near inland seas, where- were as follows; as in northern Europe, this bird occurs in coastal Most Frequently Observed Raptors. European plains. The population in Turkey was estimated at

Honey-buzzard {Pernis apivorus) . The honey buzzard no more than 100 pairs (Vaassen 2001). Most of is a summer visitor and migrant. It was seen during the individuals of this species have short migratory 15 surveys between March-September 2001, in- ranges. cluding one observation of 550 migrants in Istan- Egyptian Vulture {Neophron percnopterus) . The . . . .

38 Turan VoL. 39, No. 1

Egyptian Vulture is one of the four vulture species observed only on five occasions in September

that is widespread in Turkey. A summer visitor and 2002 . rare transient, the Egyptian Vulture was seen on 13 Common Buzzard {Buteo buteo). A common, wide- surveys every month between March-September spread resident and migrant, the Common Buz- 2001 and 19 times between March-September zard was the second most frequently recorded rap- 2002, with the exception of August. tor (100 observations) in 2001. During one survey Cinereous Vulture {Aegypius monachus). This resi- in September 2001, 640 migrants were recorded.

dent raptor species is the largest bird of prey in The Common Buzzard was the most commonly-ob- Turkey. It was observed 10 times during 4 mo be- served raptor species {N — 121) in 2002. tween March-October in 2001. It was seen six Long-legged Buzzard {Buteo rufinus). A very com- times between February-November 2002, with the mon resident and abundant winter visitor, the exception of May, July, and August. Long-legged Buzzard was generally seen in semi-

Short-toed Snake-Eagle ( Circaetus gallicus) . An abun- arid and mountainous areas. It was the most fre- dant summer visitor and migrant species, the quently recorded raptor species {N = 109) in 2001, Short-toed Snake-Eagle was seen on 23 occasions and the second most frequently recorded raptor and during every month between February-Octo- {N= 115) in 2002.

ber 2001. During two surveys in September, 25 and Lesser Spotted Eagle {Aquila pomarina) . The Lesser

34 migrants were recorded. Also, 39 migrants were Spotted Eagle is a common migrant and scarce recorded during one survey in October 2001. This summer visitor of forests with bordering plains raptor was recorded 27 times between March-No- throughout Turkey. It was recorded on 22 occa- vember 2002, with the exception of July. sions in 9 mo. In 2001, 3424 migrants were record- Western Marsh Harrier {Circus aeruginosus) This ed during one survey in September and 130 mi-

raptor is the most abundant harrier in Turkey. The grants during a survey in October. It was also seen Marsh Harrier is a resident, partial migrant, and 15 times in 2002 between April-October, with the winter visitor. Although Clark (1999) mentioned exception of July. that it was rare and local, I found that these har- Greater Spotted Eagle {Aquila clanga) A winter vis- riers were abundant. It was seen 76 times through- itor and partial migrant raptor. It was recorded out 2001 and 109 times in every month of 2002. eight times in 2001 and nine times in 2002.

Northern Harrier ( Circus cyaneus) Although a very Imperial Eagle {Aquila heliaca) . The Imperial Ea- common winter visitor and migrant, the Northern gle is a rare resident, winter visitor, and migrant in

Harrier was very rare in summer. I recorded it on Turkey. It was observed in small numbers in 2001 37 occasions between September-April 2001, 57 and on 12 occasions between February-August times and during every month of 2002, with the 2002. The Imperial Eagle has been classified as a

exception of June-August. globally-threatened species (Collar et al. 1994), Montagu’s Harrier {Circus pygargus). A summer and breeding populations have declined through- * visitor and migrant, Montagu’s Harrier was seen 15 out southern Europe, North Africa, and the Mid- times in every month of 2001, with the exception dle East (Cramp and Simmons 1980, Biber 1990, of May, June, October, and December. This harrier Clark 1999). was observed on 11 occasions in 2002 between Golden Eagle {Aquila chrysaetos). The most wide- April-October, with the exception of May and July. spread resident eagle species in Turkey, the Gold- Northern Goshawk {Accipiter gentilis) This uncom- en Eagle was seen on 18 occasions in 8 mo of 2001 mon resident was seen on 10 occasions in 7 mo of and 15 times in different regions in 2002, with the 2001, and six times in 5 mo of 2002. exception of August and September. Even though Eurasian Sparrowhawk {Accipiter nisus). A com- Vaassen (2001) suggested that Golden Eagles were mon resident and very common migrant in Turkey. the most common Aquila in Turkey (2000-3000 This species was recorded 58 times in 2001 and pairs) there 54 , were no Golden Eagles sighted in Feb- times during every month in 2002. ruary, April, August, and December in 2001. Levant Sparrowhawk {Accipiter brevipes). The Le- Booted Eagle {Hieraaetus pennatus). The Booted vant Sparrowhawk was a summer visitor and mi- Eagle is a common summer visitor and migrant. It grant species. During one survey in September breeds in forests with a mixture of open ground in

2001, 68 migrants were recorded. However, it was hilly or mountainous topography. Booted Eagles . . . . .

March 2005 Status of Diurnal Raptors in Turkey 39 were seen on 14 occasions during 8 mo of 2001 ber 2001. This bird was observed on 12 occasions and 15 times during 6 mo of 2002. in 2002, outside of the breeding season (May—Au-

Bonelli ’s Eagle (Hieraaetus fasciatus) A rarely seen gust) . resident species, Bonelli’s Eagles were recorded Eleonora ’s Falcon {Falco eleonorae) This raptor spe- five times during 4 mo of 2001, and five times dur- cies is a rare summer visitor, but it is widespread ing 5 mo of 2002. European populations of this in Turkey during migration. The Eleonora’s Falcon species have experienced a marked decline and was observed on six occasions in 2001 and only this raptor is considered a vulnerable species (Ro- twice in 2002. camora 1994, Clark 1999). Real et al. (1996) esti- Merlin {Falco columbarius) The Merlin is a fairly mated that a peripheral, sedentary population with common winter visitor and migrant found ca. 1000 pairs inhabits the Mediterranean area of throughout the country. Merlins from central Asia

Europe. also winter in Turkey (Clark 1999). In 2001, it was Osprey {Pandion haliaetus). The Osprey is a rare observed on nine occasions during January, Feb- summer visitor and migrant raptor. Ospreys were ruary, April, and December 2001, and 13 times recorded seven times in February, March, August, during January, April, May, September, and Octo- September, and November 2001, and four times in ber of 2002. However, no evidence of breeding was 4 mo of 2002. The Osprey has historically bred in recorded. the Marmara and Black Sea regions (Vaassen Eurasian Hobby {Falco subbuteo) A common sum- 2001). However, even though they were observed, mer visitor, the hobby breeds in a variety of habi- they have not been found breeding recently in that tats. It was observed on 22 occasions, between region (Vaassen 2001). April-October 2001, and 22 times between April- Lesser Kestrel {Falco naumannt). The Lesser Kes- October 2002, with the exception of July. trel is a small colonially-nesting falcon distributed Peregrine Falcon {Falco peregrinus) . The Peregrine throughout Turkey. It is present in the summer Falcon is a fairly common summer visitor and res- and is a rare winter visitor that mostly winters in ident. This large falcon was seen on 20 occasions Africa and south of the Sahara Desert (Cramp and during 11 mo of 2001, with the exception of May. Simmons 1980, Clark 1999). This species was ob- It was also seen 27 times in 9 mo of 2002, with the served nine times between March-October. During exception of May, September, and October. Clark two surveys in August 2001, 70 and 10 migrants (1999) stated that most populations of peregrines were recorded, respectively, and 25 migrants were had a marked decline between 1950-70 due to var- recorded during one survey in September. In 2002, ious persistent pesticides. it was observed on 23 occasions in every month, Infrequently-detected Species. The Red Kite with the exception of September. The Lesser Kes- {Milvus milvus) and Rough-legged Hawk {Buteo la- trel was previously considered as one of the most gopus) were recorded only once in both 2001 and abundant raptors in Europe (Bijleveld 1974), but 2002. The Pallid Harrier {Circus macrourus) and it has recently become extinct in several countries Steppe Eagle {Aquila nipalensis) were recorded only (Biber 1990). Parr and Yarar (1993) stated that the once in 2001, and four times in 2002. Both species population of Lesser Kestrels in Turkey was 1500- only migrate through Turkey. However, sporadic 3500 pairs, ranking as the second-largest popula- breeding records of Pallid Harrier in Turkey have tion in the world. been recorded (Clark 1999). Turkey is the primary

Eurasian Kestrel {Falco tinnunculus) . The Eurasian geographic region supporting Bearded Vultures Kestrel is the most widespread resident falcon spe- {Gypaetus barbatus) in Europe and the Middle East. cies in Turkey. This falcon was found mostly in It is widespread across Turkey into the Caucasus open country, on plains, and arable fields. They (Clark 1999) and a very rare and local resident in were also common in urban habitat. It was ob- high mountains; however, its numbers are declin- served on 98 occasions in 2001 and 97 times in ing. Svennson et al. (1999) estimated that there 2002. were only 500 pairs left within this region. Bearded Red-footed Falcon {Falco vespertinus) The Red-foot- Vulture was recorded only once in 2001, and five ed Falcon is a migrant and rare summer visitor in times in 2002. The Eurasian Griffon {Gyps fulvus)

Turkey. During two surveys in August 2001, 10 and is primarily a resident in the mountains of the 70 migrants were recorded, respectively. Also 25 Mediterranean area, particularly in Turkey. Breed- migrants were seen during one survey in Septem- ing griffons in most of Turkey are migratory and /

40 Turan VoL. 39, No. 1 leave in winter (Clark 1999). The population in the Bibby, C., M. Jones, and S. Marsden. 1998. Expedition western half of the country has undergone a sig- field techniques, bird surveys. Royal Geographic So- nificant decline (Kasparek 1992). Griffons were ciety, London, U.K.

, N.D. Burgess, and D.A. Hill. 2000. Bird census seen on five occasions in 2002. The Sooty Falcon techniques. 2nd Ed. Academic Press, London, U.K. {Falco concolor) was recorded on two occasions in Biber, J.P. 1990. Action plan for the conservation of west- 2001 and not seen in 2002. Tanner Falcons {Falco ern Lesser Kestrel Falco naumanni populations. ICBP biarmicus) and Saker Falcons {Falco cherrug) were Study Report, No. 41, Cambridge, U.K. seen on 2-5 occasions both in 2001 and 2002. The Bijleveld, M. 1974. Birds of prey in Europe. Mac Millan in last species was observed only once 2002. Press, London, U.K. Species Not Recorded in 2001 and 2002. The Clark, W.S. 1999. A field guide to the raptors of Europe, Barbary Falcon {Falco pekgrinoides) was not ob- the Middle East, and North Africa. Oxford Univ served in either 2001 or 2002. This species was Press, New York, NY U.S.A. seen in Birecik, southeastern Anatolia in 1990-94, Collar, N.J., M.J. Crosby, and A.J. Stattersfield. 1994 but has not been observed since. Therefore, I clas- Birds to watch 2: the world list of threatened birds Birdlife Conservation Series No.4. BirdLife Interna- sify it as a “vagrant.” The Oriental Honey-buzzard {Pernis ptilorhynchus) and Black-winged Kite {Elan- tional, Cambridge, U.K. , Comas, A., P. Feliu, H. Perxacs, and D. Saavedra. 2001. us caeruleus) are very rare raptor species. They were http: //www.osme.org/osmetrip/turkl9.html. not sighted in 2001 or 2002. Cramp, S. and K.E.L. Simmons (Eds.). 1980. The birds of Due to their position on top of the food chain, the western Palearctic. Vol. 2. Oxford Univ. Press, Ox- diurnal raptors occur in relatively small numbers ford, U.K. and, therefore, are more subject to declines or ex- Demircan, S. 2001. Important records on Black Kte Mtl- tinctions than other birds. The problems facing vus migrans. Ibibik 1:1—29. raptors in Turkey are similar to that elsewhere. Ag- Dyczkowski, J. 2001. Trip reports, Turkey, http:// ricultural insecticides are still responsible for the www.osme.org/ osmetrip/turkl 5.html. decline of some raptor populations in Turkey Eriksen, H. and J. Eriksen. 2002. Trip reports, Turkey (Vaassen 2001). In addition, sparrowhawks are http://www.osme.org/osmetrip/ turk21.html. hunted in northeastern Turkey (Turan 1986). Erol, E., V. Stohr, and W. Denk. 1982. Die naturraum- Tiirkei. Karte 1: 2000000. Tiib- Though not very common, I have documented liche Gliederung der inger Atlas des Vorderen Orients, Blatt VII 2. Univ. that some raptors were captured for falconry. Oc- A Tubingen, Tubingen, Germany. casionally, a large sum will be paid in the Middle Forsman, D. 1998. The raptors of Europe and the Middle East for a bird trained for falconry (Turan 1986). East: a handbook of field identification. T. & A.D. Poy- Although the Turkish government has initiated an ser, Calton, U.K. intensive hunter-training program, there still exists Gensbol, B. 1986. Collins guide to the birds of prey of a of illegal hunting. problem Britain and Europe, North Africa, and the Middle This study summarizes data obtained from field East. Collins Press, London, U.K. surveys carried out in different regions of Turkey Giannatos, G. 2002. Trip reports, Turkey, http:/ over a 2-yr period. No comparable data from pre- www.osme.org/osmetrip/turkl7.html. vious years were available. For this reason, I urge Glutz, U.N., K.M. Bauer, and E. Bezzel. 1987. Hand- that future surveys be conducted to track the buch der Vogel Mitteleuropas. Aula, Wiesbaden, Ger- change of raptor populations in Turkey. many. Kasparek, M. 1992. Die Vogel der Tiirkei: eine ubersicht. Acknowledgments Kasparek Verlag, Heidelberg, Germany.

Krwan, G.M., R.P. Martins, G. Eken, and P. Davidson I want to thank the many volunteer birders who con- 1998. Checklist of the birds of Turkey. Sandgrouse 1 tributed to this list. I am very grateful to W. Mahoney and I. Ozyildirim for improving the English of this paper, 1-32. also to the anonymous referees for their valuable com- Kziroglu, I. 1989. Tiirkiye Ku§lari. Desen Ofset, Ankara, ments on earlier drafts. Turkey.

, L. Turan, and A. Erdogan. 1993. Ein Beitrag zur Literature Cited Tiirkischen Greifvogelfauna und ihrer Gefahrdungs- Balmer, D. and K. Betton. 2001. Around the region grade. H. U. Egit. Fak. Derg. 9:271-279. 2001 Turkey. Sandgrouse2^:15&. Ktm, R. 2002. Trip reports, Turkey, http://www.osme.

AND . 2002. Around the region 2002 Tur- org/osmetrip/ turk20.html. key. Sandgrouse Kumerloeve, H. 1970. Zur kenntnis der Avifauna der March 2005 Status of Diurnal Raptors in Turkey 41

Kleinasiens und der Europaeischen Tiirkei. Istanbul. SVENNSON, L., P.J. Grant, K. Mullarney, and D. Zetter-

Tip. Fak. Mecm. 35:85-160. STROM. 1999. Collins bird guide. Harper Collins Pub-

Merril, I. 2001. Trip reports, Turkey, http://www.osme. lishers, London, U.K. org/osmetrip/ turkl6.html. Toygar e-group. 2001. Recent records in Toygar e-group

Parr, S. and M. Yarar. 1993. Preliminary results from a on the bird species in Turkey, http://groups.yahoo. Lesser Kestrel survey of Turkey, spring 1993. Ornithol. com/ group/ toygar.

. 2002. Recent records in Toygar e-group on the Soc. Middle East Bull. 31:8—10. species in Turkey, http:/ /groups.yahoo.com/ 1996. Estatus, de- bird Real, J., S. Manosa, and J. Godina. group/ toygar. mografia y conservacion del aquila perdicera en el Turan, L. 1986. Hunting with using of the birds of prey Mediterraneo. Pages 83-90 inj. Muntaner and J. May- in Turkey./. Fac. Educ. 12:207-210. ol [Eds.], Biologia y conservacion de las rapaces Med- Vaassen, E.W. 2001. Recent status of birds of prey in Tur- iterraneas, 1994. BirdLife International, Madrid, key. Poster at 4* Eurasian Congress on Raptors, 25- Spain. 29 September 2001, Seville, Spain, Rocamora, G. 1994. Bonelli’s Eagle {Hieraaetusfasciatus). Weaver, P. 1981. The birdwatcher’s dictionary. T. 8c A.D. Pages 184-185 in G.M. Tucker and M.F. Heath [Eds.], Poyser Ltd., Cambridge, U.K. Birds in Europe: their conservation status. BirdLife Weick, F. 1980. Greifvogel der Welt. P. Parey, Hamburg, International, Cambridge, U.K. Germany. Swann, B. 2001. Trip reports, Turkey, http://www.osme. org/osmetrip/turkl4.html. Received 28 July 2003; accepted 14 November 2004 42 Turan VoL. 39, No. 1

Appendix. Survey locations, distances of transects, sampling dates, number of spot counts, total number of raptors and raptor species for each survey.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province / District Grid Date Counts Species OF Raptors Type (m)

Edirne-Tekirdag B2 4 Jan 01 4 70 Line 10 000 Izmir El 6 Jan 01 1 1 1 Spot Eiayseri-Palas ElO 8 Jan 01 5 4 20 Spot Izmir-Gediz El 21 Jan 01 9 7 19 Spot Gaziantep-Karkamis G12 25 Jan 01 2 1 400 Spot Istanbul-Buyukcekmece B3 26 Jan 01 5 2 2 Spot Ankara-Mogan D7 27 Jan 01 7 11 Line 9000 Izmir-Karaburun El 28 Jan 01 1 1 1 Spot Bursa-Uludag C4 10 Feb 01 1 1 2 Spot Ankara-Mogan D7 11 Feb 01 2 2 Line 9000 Ankara D7 12 Feb 01 1 1 1 Spot Ankara-Mogan D7 12 Feb 01 4 7 Line 9000 Burdur Lake F5 12 Feb 01 1 0 0 Spot Kocaeli-Korfez C4 15 Feb 01 1 1 1 Spot Edirne B1 17 Feb 01 1 1 20 Spot Ankara-Mogan D7 19 Feb 01 2 4 Line 9000 Kayseri-Palas ElO 25 Feb 01 4 2 5 Spot Burdur-Salda, Yarisli F5 28 Feb 01 2 3 5 Spot Hatay-Subasi GIO 2 Mar 01 1 0 0 Spot Kayseri ElO 2 Mar 01 1 0 0 Spot Kayseri ElO 3 Mar 01 1 1 1 Spot Mugla-Bodrum F2 3 Mar 01 1 0 0 Spot

Hatay-Samandag GIO 4 Mar 01 1 1 1 Spot

Izmir El 4 Mar 01 1 1 1 Spot Samsun-Kampus, Golet Bll 4 Mar 01 2 2 Line 2200

Hayay-Subasi GIO 5 Mar 01 1 2 2 Spot

Mugla-Bodrum F2 5 Mar 01 1 1 1 Spot

Corum-Ipekli C9 6 Mar 01 1 0 0 Spot Izmir El 6 Mar 01 2 0 0 Spot Adana-Akyatan GIO 7 Mar 01 1 6 6 Spot Ankara-Eymir C7 7 Mar 01 1 2 8 Spot Ankara-K. hamam C7 9 Mar 01 1 6 11 Spot Hatay-Samandag GIO 9 Mar 01 1 0 0 Spot Hatay-Samandag GIO 9 Mar 01 1 0 0 Spot Hatay-Samandag GIO 9 Mar 01 1 1 23 Spot Istanbul-Cekmekoy B3 10 Mar 01 1 0 0 Spot Istanbul-Cekmekoy B3 11 Mar 01 1 0 0 Spot Kayseri ElO 11 Mar 01 1 1 1 Spot

Edirne-Tavuk Ormani B1 17 Mar 01 1 0 0 Spot

Konya-Kulu D8 17 Mar 01 1 5 Line 4000 Mugla-Dalyan G2 17 Mar 01 1 2 5 Spot Ankara-Mogan D7 18 Mar 01 3 15 Line 9000 Ankara-ODTU D7 18 Mar 01 1 3 4 Spot

Istanbul-Bosphorus B3 18 Mar 01 1 11 662 Spot

Izmir-Gediz El 18 Mar 01 1 5 14 Spot Kayseri-Erciyes, Sultan Sazligi ElO 18 Mar 01 4 4 13 Spot

Edirne B1 24 Mar 01 1 1 Line 3000

Kayseri-Talas ElO 25 Mar 01 1 4 9 Spot

Istanbul-Kadikoy C3 29 Mar 01 1 1 7 Spot Adana-Tuzla GIO 5 Apr 01 1 2 6 Spot March 2005 Status of Diurnal Raptors in Turkey 43

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species OF Raptors Type (m)

Bursa-Uluabat C3 7 Apr 01 1 1 1 Spot Istanbul-Cekmekoy B3 7 Apr 01 2 0 0 Spot Ankara-Mogan D7 8 Apr 01 3 15 Line 9000 Ankara-Tuz Lake D7 8 Apr 01 1 3 103 Spot Ankara-Uyuz Lake D7 8 Apr 01 3 4 29 Spot Istanbul-Biiyukada C3 8 Apr 01 2 0 0 Spot

Bursa-Uluabat C3 10 Apr 01 1 1 3 Spot

Istanbul B3 11 Apr 01 1 8 396 Spot

Edirne B1 14 Apr 01 1 1 1 Spot Mugla-Bodrum Giilluk E2 14 Apr 01 5 3 4 Spot Ankara-Mogan D7 15 Apr 01 4 16 Line 9000 Istanbul-Sile B4 5 May 01 2 0 0 Spot Canakkale-Saros Cl 12 May 01 0 0 Line 6000

Canakkale-Gelibolu, Kesan Cl 13 May 01 1 1 Line 10000

Canakkale-Saros Cl 13 May 01 1 1 Line 6000 Ankara-Mogan D7 19 May 01 6 9 Line 9000

Istanbul-Bosphorus B3 19 May 01 1 8 87 Spot

Sanliurfa-Birecik F12 19 May 01 1 2 2 Spot Ankara-Sungurlu C9 20 May 01 3 4 Line 9000 Antalya-Belek G5 20 May 01 4 0 0 Spot

Antalya-Serik G6 20 May 01 4 1 1 Spot Corum-Hatusas, Alacahoyuk C9 20 May 01 2 1 3 Spot Ankara-ODTU D7 24 May 01 1 3 3 Spot Istanbul-Bahcekoy B3 25 May 01 1 2 4 Spot Konya-Kulu D8 26 May 01 2 4 Line 4000

Yalova C4 26 May 01 3 1 1 Spot Istanbul-Buyukcekmece B3 27 May 01 1 2 4 Spot Sanliurfa-Birecik F12 4Jun 01 1 2 2 Spot Sanliurfa-Halfeti F12 5 Jun 01 1 4 4 Spot Bolu C6 14Jun 01 1 7 17 Spot Mugla-Kavaklide re G2 14 Jun 01 1 4 6 Spot Nigde-Aladaglar F9 14 Jun 01 1 1 1 Spot Bolu-Yedigoller C6 17 Jun 01 2 2 Line 6000 Edirne-Tavuk Ormani B1 17 Jun 01 2 2 2 Spot Ankara-Beypazari C7 19 Jun 01 1 1 8 Spot Ankara-Cayirhan-Beypazari C7 19 Jun 01 1 1 Line 2500 Istanbul-Terkos B3 21 Jun 01 2 4 6 Spot Ankara-Mogan D7 24 Jun 01 2 6 Line 9000 Ankara-Mogan D7 24 Jun 01 2 6 Line 9000 Ankara-ODTU D7 24 Jun 01 1 0 0 Spot Edirne-Egribuk B1 24 Jun 01 1 2 2 Spot Konya-Kulu D8 24 Jun 01 4 9 Line 4000 Sanliurfa-Birecik F12 24 Jun 01 1 2 3 Spot Zonguldak B6 25 Jun 01 2 5 Line 3000 Sanliurfa-Birecik, Halfeti F12 29 Jun 01 2 2 4 Spot Corum-Harmancik C9 30 Jun 01 1 2 2 Spot Nigde-Aladaglar F9 30 Jun 01 1 3 4 Spot Erzurum Horasan-Kars C16 3 Jul 01 1 2 9 Spot Erzurum-Pasinler CIS 3 Jul 01 1 0 0 Spot Kars-Arpacay C18 3 Jul 01 1 2 3 Spot Igdir-Sazlik D19 4 Jul 01 1 1 20 Spot 44 Turan VoL. 39, No. 1

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Provinge/District Grid Date Counts Species OF Raptors Type (m)

Kars-Cali Lake C18 4Jul 01 1 1 1 Spot Kars-Kuyucak CIS 4Jul 01 1 3 4 Spot Mugla; Marmaris-Datca G2 4Jul 01 1 2 Line 1000 Kayseri-Derevenk ElO 5 Jul 01 1 1 4 Spot Kayseri-Hormetci ElO 5 Jul 01 1 1 1 Spot Kayseri-Sakar ElO 5 Jul 01 1 0 0 Spot Igdir D19 6 Jul 01 1 2 2 Spot Kayseri-Erciyes, Sultan Sazligi ElO 6 Jul 01 4 3 17 Spot Kayseri-Yahyali ElO 6 Jul 01 1 0 0 Spot Van E18 6 Jul 01 1 1 3 Spot Bolu-Yedigoller C6 7 Jul 01 0 0 Line 6000 Kayseri-Engir ElO 7 Jul 01 1 1 2 Spot Kayseri-Kizilirmak ElO 7 Jul 01 1 0 0 Spot Kayseri-Tuzla ElO 7 Jul 01 1 1 1 Spot Kayseri-Yertasin ElO 7 Jul 01 1 1 1 Spot Bolu-Yedigoller C6 8 Jul 01 1 0 0 Spot Izmir-Gediz El 8 Jul 01 3 1 1 Spot Hatay-Subasi GIO 9 Jul 01 1 0 0 Spot Trabzon-Sivrikaya B14 9 Jul 01 1 1 2 Spot Antalya G5 10 Jul 01 2 0 0 Spot Kastamonu B8 14 Jul 01 2 1 2 Spot Erzincan-Erzurum D15 17 Jul 01 3 3 Line 5000 Erzurum-Guneykaya C16 18 Jul 01 1 4 4 Spot Agri-Eleskirt D18 19 Jul 01 3 4 4 Spot Kayseri-Sultan Sazligi ElO 19 Jul 01 4 1 1 Spot Van-Catak E18 20 Jul 01 1 4 4 Spot Bursa-Uluabat C3 21 Jul 01 1 0 0 Spot Erzin can-Eksisu D14 21 Jul 01 1 3 8 Spot Van-Golboga Lake E18 21 Jul 01 1 3 3 Spot Ankara-ODTU D7 22 Jul 01 1 0 0 Spot E dirne-Golbaba B1 22 Jul 01 1 7 9 Spot Erzincan-Eksisu D14 22 Jul 01 1 3 5 Spot Erzincan-Eirat river D14 22 Jul 01 2 6 11 Spot Erzincan-Firat river D14 22 Jul 01 1 0 0 Spot Erzincan-Mutu D14 22 Jul 01 1 3 5 Spot Rize-Ayder B15 22 Jul 01 1 2 7 Spot Trabzon-Erzurum Yolu C14 22 Jul 01 2 2 51 Spot Bitlis-Tatvan, Ahlat E17 23 Jul 01 2 5 5 Spot Rize-Ayder B15 23 Jul 01 1 1 1 Spot Sanliurfa-Birecik F12 23 Jul 01 1 1 1 Spot Erzincan D14 24 Jul 01 1 5 16 Spot Rize-Ayder B15 24 Jul 01 1 0 0 Spot Sanliurfa-Birecik El 2 24 Jul 01 1 1 1 Spot Sanliurfa-Birecik El 2 24 Jul 01 1 1 1 Spot Agri-Dogubeyazit D18 25 Jul 01 1 1 1 Spot Bursa-Akcalar C4 25 Jul 01 1 0 0 Spot Erzincan-Isikpinar D14 25 Jul 01 1 3 4 Spot Erzincan D14 26 Jul 01 1 1 2 Spot Antalya-Kemer G5 27 Jul 01 1 1 1 Spot Ankara-ODTU D7 28 Jul 01 1 0 0 Spot Bursa-Uluab at C3 29 Jul 01 1 1 1 Spot Edirne B1 29 Jul 01 1 1 Line 1000 March 2005 Status of Diurnal Raptors in Turkey 45

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species OF Raptors Type (m)

Edirne B1 29 Jul 01 1 1 1 Spot

Kayseri-Derebag ElO 29 Jul 01 1 1 Line 2000

Hatay-Samandag GIO 30 Jul 01 1 1 1 Spot Nevsehir-Avanos E9 31 Jul 01 1 3 2 Spot Ankara-Mogan D7 2 Aug 01 3 9 Line 9000 Ankara-Nallihan C7 3 Aug 01 2 3 5 Spot

Kayseri-Derebag ElO 3 Aug 01 1 1 1 Spot

Ankara-Beynam D7 5 Aug 01 1 4 18 Spot Ankara-Mogan D7 5 Aug 01 5 11 Line 9000

Ankara-Nallihan C7 5 Aug 01 1 2 4 Spot

Mugla-Didim F2 8 Aug 01 1 0 0 Spot

Mugla-Milas F2 9 Aug 01 1 0 0 Spot

Mugla-Bodrum F2 11 Aug 01 1 0 0 Spot

Edirne-Uzunkoprii B1 12 Aug 01 1 3 3 Spot Balikesir-Manyas C2 13 Aug 01 2 2 2 Spot Balikesir-Manyas C2 14 Aug 01 1 3 3 Spot

Mugla-Bodrum F2 15 Aug 01 1 1 1 Spot Bursa-Ulubat C3 16 Aug 01 2 0 0 Spot

Kutahya; Bozoyuk-Inonu D4 17 Aug 01 1 1 Line 1400 Mugla-Bodrum F2 17 Aug 01 1 0 0 Spot Mugla-Dalaman F2 17 Aug 01 1 1 1 Spot Mugla-Marmaris G2 17 Aug 01 1 0 0 Spot Kutahya-Altuntas D4 18 Aug 01 1 2 6 Spot Edirne-Golbaba B1 19 Aug 01 1 3 5 Spot Burdur Lake F5 21 Aug 01 1 1 1 Spot Burdur-Salda F5 22 Aug 01 1 1 1 Spot

Burdur-Yarisli F5 22 Aug 01 1 1 1 Spot Ankara-Mogan D7 24 Aug 01 2 81 Line 9000 Izmir-Odemis E2 25 Aug 01 1 1 1 Spot

Ankara-K. hamam C7 26 Aug 01 1 1 6 Spot

I s tanbul-Camlic a C3 26 Aug 01 1 2 554 Spot Izmir-Aliaga El 26 Aug 01 1 0 0 Spot Izmir-Odemis E2 26 Aug 01 1 1 19 Spot Istanbul-Bahcekoy B3 28 Aug 01 1 0 0 Spot Kayseri-Sivas ElO 29 Aug 01 2 19 Line 5000 Konya-Kulu D8 29 Aug 01 8 19 Line 4000 Sivas-Erzincan D12 29 Aug 01 2 20 Line 5000 Ankara-ODTU D7 30 Aug 01 1 5 7 Spot Burdur Lake F5 30 Aug 01 1 0 0 Spot Erzurum-Sarikamis C17 30 Aug 01 0 0 Line 5000 Erzurum-Sarikamis C17 30 Aug 01 1 1 1 Spot Eskisehir-Porsuk D6 30 Aug 01 1 0 0 Spot Kars-Sarikamis C18 30 Aug 01 0 0 Line 5000 Ankara-K. hamam-Cevreyolu C7 31 Aug 01 1 3 3 Spot Kars C18 31 Aug 01 4 4 13 Spot Agri-Dogubeyazit D18 1 Sep 01 1 0 0 Spot Istanbul-Bahcekoy B3 6 Sep 01 2 2 13 Spot Istanbul-Bahcekoy B3 7 Sep 01 2 1 7 Spot Konya-Kulu D8 8 Sep 01 3 4 Line 4000 Antalya-Saklikent G5 14 Sep 01 1 5 7 Spot Antalya-Saklikent G5 15 Sep 01 1 0 0 Spot 46 Turan VoL. 39, No. 1

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species OF Raptors Type (m)

Edirne-Kesan Cl 15 Sep 01 2 2 4 Spot Mugla-Bodrum Giilluk F2 15 Sep 01 7 3 3 Spot Ankara-Cayirhan C7 16 Sep 01 1 5 Line 2500 Ankara-Cayirhan Cl 16 Sep 01 1 1 3 Spot

An talya-Sakliken t G5 16 Sep 01 1 5 6 Spot Bursa-Uluabat C3 16 Sep 01 8 2 11 Spot Edirne-Enez B1 16 Sep 01 1 3 9 Spot Mugla-Bodrum Giilluk F2 16 Sep 01 3 0 0 Spot Mersin-Goksu Cl 18 Sep 01 1 1 1 Spot Sanliurfa-Birecik-Vadi FI 2 19 Sep 01 2 1 1 Spot Sanliurfa-Birecik-Fidanlik FI 2 21 Sep 01 4 0 0 Spot Ankara-Bilke nt D7 22 Sep 01 1 2 4 Spot Samsun BII 22 Sep 01 4 1 1 Spot Sanliurfa-Birecik-Halfeti Yolu FI 2 22 Sep 01 1 3 Line 1500 Bursa-Uluabat C3 23 Sep 01 1 6 20 Spot Istanbul-Camlica C3 23 Sep 01 1 0 0 Spot Sanliurfa-Birecik-Karkamis FI 2 23 Sep 01 1 1 Spot 2000 Istanbul-Bahcekoy B3 24 Sep 01 2 7 488 Spot Istanbul-Bahcekoy B3 25 Sep 01 2 8 191 Spot Hatay-Belen GIl 28 Sep 01 1 7 3539 Spot Mugla-Bodrum Giilluk F2 29 Sep 01 3 3 6 Spot Mugla-Bodrum Tuzla F2 29 Sep 01 2 0 0 Spot Ankara-Mogan D7 30 Sep 01 2 4 Line 9000 Konya-Kulu D8 30 Sep 01 1 1 Line 4000 Ankara-Mogan D7 1 Oct 01 4 8 Line 9000 Nigde-Aladaglar F9 1 Oct 01 1 3 4 Spot Elazig-Hazar E14 3 Oct 01 2 5 121 Spot Istanbul-Bahcekoy B3 3 Oct 01 1 7 80 Spot Istanbul-Bahcekoy B3 4 Oct 01 1 1 2 Spot Istanbul-Bahcekoy B3 5 Oct 01 1 4 17 Spot Corum C9 6 Oct 01 1 0 0 Spot Izmir-Gediz El 6 Oct 01 1 3 3 Spot

Kayseri-Talas, Sarimsakli ElO 6 Oct 01 2 1 1 Spot Ankara-Mogan D7 7 Oct 01 4 4 Line 9000 Burdur Lake F5 7 Oct 01 1 0 0 Spot Izmir-Aliaga El 7 Oct 01 1 2 2 Spot Kayseri-Talas, Engir EIO 7 Oct 01 2 0 0 Spot Istanbul B3 10 Oct 01 1 5 439 Spot Ankara-K. hamam C7 13 Oct 01 4 6 48 Spot Bursa-Uluabat C3 13 Oct 01 1 2 2 Spot Gumushane-Siran CI4 13 Oct 01 2 2 l.ine 5000 Konya-Kulu D8 13 Oct 01 0 0 Line 4000 Samsun-Kurupelit Bll 13 Oct 01 1 1 Line 1500 Ankara-Mogan D7 14 Oct 01 3 3 Line 9000 Bursa-Uluabat C3 14 Oct 01 7 1 15 Spot Kayseri EIO 14 Oct 01 3 2 9 Spot Konya-Kulu D8 20 Oct 01 3 3 Line 4000 Bursa-Uluabat C3 21 Oct 01 3 6 Spot Ankara-Mogan D7 27 Oct 01 1 3 6 Line 9000 Konya-Kulu D8 27 Oct 01 3 3 Line 4000 Ankara-Mogan D7 28 Oct 01 4 10 Line 9000 March 2005 Status of Diurnal Raptors in Turkey 47

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species OF Raptors Type (m)

Ankara-Mogan D7 29 Oct 01 2 2 Line 9000 Konya-Kulu D8 3 Nov 01 2 3 Line 4000

Ankara-Mogan D7 1 Dec 01 4 6 Line 9000

Konya-Kulu D8 1 Dec 01 1 3 Line 4000

Mugla-Bodrum F2 1 Dec 01 4 4 12 Spot Bursa-Uluabat C3 2 Dec 01 7 5 24 Spot

Samsun Bll 2 Dec 01 1 1 1 Spot Mugla-Bodrum Tuzla F2 5 Dec 01 2 1 2 Spot Konya-Kulu D8 8 Dec 01 2 2 Line 4000

Ankara-ODTU D7 10 Dec 01 1 1 1 Spot

Mugla-Bodrum Giilluk F2 15 Dec 01 1 6 20 Spot Konya-Kulu D8 16 Dec 01 2 2 Line 4000 Mugla-Bodrum Tuzla F2 16 Dec 01 1 3 18 Spot Nevsehir-Avanos, Edzilirmak E9 17 Dec 01 0 0 Line 3000 Nevsehir-Kizilirmak Valley E9 17 Dec 01 3 6 Line 3000

Ankara-Ovacay D7 18 Dec 01 1 6 11 Spot Istanbul-K., B. Cekmece B3 19 Dec 01 3 4 25 Spot

Edirne B1 21 Dec 01 1 1 1 Spot Ankara-Mogan D7 23 Dec 01 4 4 Line 9000 Izmir-Gediz El 23 Dec 01 2 5 8 Spot Kayseri ElO 23 Dec 01 2 0 0 Spot

Ankara-Bilkent D7 24 Dec 01 1 1 1 Spot

Mugla-Bodrum Tuzla F2 26 Dec 01 3 1 1 Spot

Izmir-Aliaga El 29 Dec 01 1 1 2 Spot

Konya-Kulu D8 29 Dec 01 1 1 Line 4000

Mersin-Kazanli G7 29 Dec 01 1 1 1 Spot Ankara-Mogan D7 30 Dec 01 4 7 Line 9000

Istanbul-Buyukcekmece B3 30 Dec 01 3 1 2 Spot

Kayseri-Engir ElO 30 Dec 01 1 1 1 Spot

Kayseri-Kizilirmak ElO 30 Dec 01 1 1 1 Spot

Kayseri-Palas ElO 30 Dec 01 1 1 3 Spot

Kayseri-Yertasin ElO 30 Dec 01 1 3 4 Spot

Mugla-Bodrum Giilluk F2 30 Dec 01 3 1 1 Spot Mugla-Bodrum Tuzla F2 30 Dec 01 1 0 0 Spot Ankara-K. hamam C7 31 Dec 01 1 0 0 Spot Ankara-Mogan D7 31 Dec 01 3 15 Line 9000 Mugla-Bodrum F2 31 Dec 01 2 4 7 Spot

Bursa-Kampus C4 1 Jan 02 1 2 6 Spot

Bursa-Uluabat C3 1 Jan 02 1 2 6 Spot Adana-Karatas GIO 3 Jan 02 3 5 5 Spot Mugla-Milas, Tuzla F2 5 Jan 02 1 6 12 Spot Izmir-Gediz El 6 Jan 02 1 6 8 Spot Mugla-Milas, Giilluk F2 6 Jan 02 1 6 12 Spot Istanbul-Kiiciiksu C3 10 Jan 02 1 0 0 Spot An kara-Nallih an C7 12 Jan 02 5 12 Line 2000 Ankara-Nallihan G7 12 Jan 02 1 4 6 Spot Kayseri-Merkez ElO 12 Jan 02 1 1 1 Spot Mugla-Milas, Tuzla F2 12 Jan 02 1 2 4 Spot Burdur Lake F5 13 Jan 02 1 0 0 Spot Bursa-Uluabat C3 13 Jan 02 10 4 40 Spot Mugla-Milas, Tuzla F2 14 Jan 02 1 7 Line 1000 48 Turan VoL. 39, No. 1

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance PROVINCFyDiSTRICT Grid Date Counts Species OF Raptors Type (M)

Isparta-Egirdir F4 19 Jan 02 1 1 1 Spot Istanbul-Buyukcekmece B3 19 Jan 02 1 1 3 Spot Mugla-Milas, Tuzla F2 19 Jan 02 1 2 4 Spot Kastamonu-Kure-Varla B9 20 Jan 02 4 4 Line 2500 Kirklareli-Igneada B2 20 Jan 02 3 2 11 Spot Konya-Ankara D7 20 Jan 02 4 13 Line 5000 Mugla-Milas, Gulliik E2 20 Jan 02 1 6 15 Spot Izmir-Gediz El 25 Jan 02 1 6 19 Spot Edirne-Merkez B1 26 Jan 02 2 2 3 Spot Izmir-Gediz El 26 Jan 02 1 8 51 Spot Mugla-Milas, Tuzla F2 26 Jan 02 2 1 1 Spot Bursa-Uluabat C3 27 Jan 02 9 2 13 Spot Izmir-Korfez El 27 Jan 02 1 0 0 Spot Izmir-Cesme El 1 Feb 02 2 4 5 Spot Konya-Kulu D8 1 Feb 02 0 0 Line 4000 Ankara-Bilkent D7 2 Feb 02 2 0 0 Spot Aydin-Azap Lake F2 2 Feb 02 1 0 0 Spot Aydin-B. Menderes F2 2 Feb 02 1 7 27 Spot Aydin-Bafa F2 2 Feb 02 1 3 11 Spot Mugla-Milas, Tuzla F2 2 Feb 02 4 1 5 Spot Sinop AlO 2 Feb 02 2 0 0 Spot Sinop-Gerze B9 2 Feb 02 2 2 Line 10 000 Sinop-Samsun BIO 2 Feb 02 2 12 Line 10 000 Smop-Sarikum Lake BIO 2 Feb 02 3 5 11 Spot Balikesir-Manyas C2 3 Feb 02 1 3 60 Spot Edirne-Merkez B1 3 Feb 02 3 1 23 Spot Istanbul-Terkos B3 3 Feb 02 8 3 31 Spot Kayseri-Engir ElO 3 Feb 02 1 1 3 Spot EAyseri-Sarimsakli ElO 3 Feb 02 1 0 0 Spot Kayseri-Tuzla ElO 3 Feb 02 1 1 3 Spot Kirklareli-Igneada B2 3 Feb 02 2 3 8 Spot Konya-Kulu D8 3 Feb 02 2 2 Line 4000 Mugla-Milas-Tuzla F2 3 Feb 02 2 13 Line 1000 Amasya-Yedikir CIO 4 Feb 02 2 2 3 Spot Kayseri-Sultan Sazligi ElO 6 Feb 02 1 1 10 Spot Ankara-Nallihan C7 9 Feb 02 1 7 11 Spot Edirne-Golbaba B1 10 Feb 02 2 2 8 Spot

Ankara-Sogiitozu D7 11 Feb 02 1 1 11 Spot Burdur Lake F5 16 Feb 02 1 0 0 Spot Bursa-Kocacay C3 16 Feb 02 4 3 7 Spot Konya-Kulu D8 16 Feb 02 1 1 Line 4000 Mugla-Milas, Tuzla F2 16 Feb 02 2 1 2 Spot Denizli-Acigol F4 17 Feb 02 1 0 0 Spot Izmir-Gediz El 17 Feb 02 1 1 2 Spot Adiyaman-Golbasi F13 19 Feb 02 0 0 Line 4000 Istanbul-Yedikir B3 21 Feb 02 3 2 3 Spot Konya-Kulu D8 22 Feb 02 2 2 Line 4000 Mugla-Milas, Mumcular F2 22 Feb 02 1 1 Line 1200 Ankara-Ovacay D7 23 Feb 02 3 8 14 Spot Mugla-Milas, Tuzla F2 23 Feb 02 0 0 Line 1000 Mugla-Tuzla F2 23 Feb 02 2 0 0 Spot Ankara-ODTU D7 25 Feb 02 1 1 1 Spot March 2005 Status of Diurnal Raptors in Turkey 49

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species OF Raptors Type (m)

Samsum-Ladik BlI 25 Feb 02 4 3 5 Spot Istanbul-Yedikir B3 26 Feb 02 4 2 2 Spot Burdur Lake F5 28 Feb 02 3 0 0 Spot Samsun-Kizilirmak BIO 28 Feb 02 2 36 Line 2200 Izmir-Gediz El 1 Mar 02 7 15 0 Spot Ankara-ODTU D7 2 Mar 02 1 3 6 Spot Izmir-Aliaga El 2 Mar 02 1 2 2 Spot Konya-Kulu D8 2 Mar 02 2 2 Line 4000

Mugla-Datca G2 2 Mar 02 1 1 2 Spot Ankara-Mogan D7 3 Mar 02 3 4 Line 9000

Izmir-Gediz El 3 Mar 02 1 4 14 Spot Mugla-Tuzla F2 3 Mar 02 3 0 0 Spot Istanbul-Belgrad Or. B3 4 Mar 02 2 1 68 Spot

Kirklareli-Igneada B2 7 Mar 02 1 5 169 Spot Kayseri-Sazlik, Cayirozu EIO 8 Mar 02 1 2 4 Spot Kayseri-Sultan Sazligi, Kanal 2 EIO 8 Mar 02 1 2 Line 4000

Kirklareli-Igneada B2 8 Mar 02 1 1 1 Spot Bursa-Kocacay C3 9 Mar 02 1 4 11 Spot Kayseri-S. Sazligi, Ovaciftlik EIO 9 Mar 02 1 2 Line 1500

Kirklareli-Igneada B2 9 Mar 02 1 1 1 Spot Mugla-Milas, Tuzla F2 9 Mar 02 3 2 2 Spot Sakarya-Sapanca C5 9 Mar 02 2 0 0 Spot Ankara-Mogan D7 10 Mar 02 0 0 Line 9000 Bolu-Aladag C6 10 Mar 02 1 0 0 Spot Denizli-Acigol F4 10 Mar 02 1 2 2 Spot Kayseri-Hisarcik EIO 10 Mar 02 1 2 2 Spot Kayseri-S. Sazligi, Camuz EIO 10 Mar 02 2 2 Line 1000 Kirklareli-Igneada B2 10 Mar 02 1 0 0 Spot Izmir-Konak El 15 Mar 02 2 0 0 Spot Kayseri-Palas EIO 16 Mar 02 2 1 6 Spot Konya-Kulu D8 16 Mar 02 4 9 Line 4000

Ankara-K. hamam D7 17 Mar 02 1 7 18 Spot

Denizli-Acigol F4 17 Mar 02 1 4 6 Spot Diizce-Efteni C6 17 Mar 02 1 2 4 Spot Kayseri-Sultan Sazligi EIO 17 Mar 02 2 3 5 Spot Aksaray E8 20 Mar 02 1 0 0 Spot Aksaray-Eskil E8 20 Mar 02 1 3 4 Spot Kayse ri-De revenk EIO 20 Mar 02 1 0 0 Spot Konya-Cihanbeyli E7 20 Mar 02 1 2 2 Spot Konya-Kulu D8 20 Mar 02 2 3 Line 4000 Ankara-Mogan D7 23 Mar 02 4 7 Line 9000 Konya-Kulu D8 23 Mar 02 1 1 Line 4000 Edirne Merkez-Meric B1 24 Mar 02 1 0 0 Spot

Izmir-Gediz El 24 Mar 02 1 1 1 Spot Yalova-Tesvikiye C4 24 Mar 02 1 0 0 Spot Ankara-Beytepe D7 25 Mar 02 3 3 Line 4000 Kayseri-Palas EIO 25 Mar 02 1 2 6 Spot Isparta-Kovada F4 27 Mar 02 1 4 4 Spot Kayseri-Palas EIO 27 Mar 02 1 2 3 Spot Mugla-Milas, Tuzla F2 27 Mar 02 1 2 2 Spot Ordu B12 27 Mar 02 2 2 Line 2000 50 Turan VoL. 39, No. 1

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species OF Raptors Ttpe (m)

Ankara-Mogan D7 30 Mar 02 5 18 Line 9000 Kayseri-Palas ElO 30 Mar 02 1 2 7 Spot Kayseri-Palas, Kizilirmak ElO 30 Mar 02 2 1 2 Spot Bilecik-Osmaneli C5 31 Mar 02 1 3 5 Spot Edirne Merkez-Meric BI 31 Mar 02 1 1 2 Spot Izmir-Gediz El 31 Mar 02 2 10 27 Spot Kayseri-Palas ElO 31 Mar 02 1 2 3 Spot Ankara-Mogan D7 1 Apr 02 2 3 Line 9000 Hatay-Subasi GIO 2 Apr 02 1 8 116 Spot Kayseri-Sultan Sazligi ElO 2 Apr 02 1 3 25 Spot Bursa-Uluabat C3 3 Apr 02 1 1 6 Spot Hatay-Samandag GIO 3 Apr 02 1 1 2 Spot Ordu-Unye B12 3 Apr 02 2 6 Line 3500 Ankara-ODTU D7 4 Apr 02 1 1 1 Spot Hatay-Subasi GIO 5 Apr 02 1 3 3 Spot Ankara-Bilkent D7 6 Apr 02 2 2 2 Spot Ankara-Mogan D7 6 Apr 02 4 6 Line 9000 Edirne-Golbaba Bl 6 Apr 02 2 5 9 Spot Konya-Kulu D8 6 Apr 02 4 9 Line 4000 Rize-Liman B15 6 Apr 02 1 0 0 Spot Ankara-Bilkent, ODTU D7 7 Apr 02 2 2 2 Spot Ankara-ODTU D7 7 Apr 02 1 5 5 Spot Bursa-Inkaya C4 7 Apr 02 1 1 1 Spot Izmir-Cigli El 7 Apr 02 1 4 4 Spot Kayseri-Hisarcik ElO 7 Apr 02 1 0 0 Spot Yalova-Akkoy C4 7 Apr 02 1 1 1 Spot Ankara-Karagol C7 8 Apr 02 1 2 2 Spot Bursa-Inkaya C4 8 Apr 02 1 0 0 Spot Izmir-Cigli El 9 Apr 02 1 4 4 Spot Afyon-Akdag E5 11 Apr 02 2 4 Line 5000 Izmir-Bornova El 11 Apr 02 1 1 1 Spot Ankara-Mogan D7 13 Apr 02 6 18 Line 9000 Diizce-Efteni C6 13 Apr 02 1 4 6 Spot Izmir-Gediz El 13 Apr 02 4 6 19 Spot Konya-Kulu D8 13 Apr 02 3 8 Line 4000 Bursa-Inkaya C4 14 Apr 02 1 0 0 Spot Edirne Bl 14 Apr 02 3 5 9 Spot Istanbul-Sariyer B3 14 Apr 02 5 371 Line 9000 Isparta-Golciik F4 16 Apr 02 1 0 0 Spot Ankara-Col Lake D7 20 Apr 02 1 1 3 Spot Ankara-Kozanli D7 20 Apr 02 1 4 10 Spot Ankara-Mogan D7 20 Apr 02 4 10 Line 9000 Ankara-Uyuz Lake D7 20 Apr 02 1 1 5 Spot Ankara-Mogan D7 21 Apr 02 2 19 Line 9000 Ankara-Nallihan C7 21 Apr 02 1 6 14 Spot Konya-Kulu D8 21 Apr 02 4 7 Line 4000 Mugla-Gokova G2 21 Apr 02 1 1 2 Spot Rize-Pazar B15 22 Apr 02 1 6 10 Spot Samsun-Kizilirmak BIO 22 Apr 02 1 1 12 Line 2200 Samsun-Yorukler Bll 22 Apr 02 1 3 3 Spot Ankara-Bilkent D7 23 Apr 02 2 1 1 Spot March 2005 Status of Diurnal Raptors in Turkey 51

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species OF Raptors Type (m)

Samsun-Kizilirmak BIO 23 Apr 02 1 3 Line 2200 Samsun Bll 24 Apr 02 1 2 5 Spot

Ankara-Ilgaz C8 25 Apr 02 1 1 1 Spot Ankara-Isik Dagi C8 25 Apr 02 1 3 3 Spot Ankara-K. hamam, Soguksu C7 25 Apr 02 1 5 11 Spot Antalya-Manavgat G6 25 Apr 02 3 15 Line 3500 Antalya-Manavgat, Akcay G6 26 Apr 02 0 0 Line 1000 Antalya-Manavgat, Sahapkopru G6 26 Apr 02 3 3 Line 1000 Eskisehir-Balikdami D6 26 Apr 02 1 2 2 Spot Eskisehir-Sivrihisar D6 26 Apr 02 1 5 204 Spot Samsun Bll 26 Apr 02 1 4 14 Spot Samsun-Balikgolu Bll 26 Apr 02 1 2 2 Spot Samsun-Incesu Bll 26 Apr 02 2 0 0 Spot Samsun-Kurtseyh Bll 26 Apr 02 1 0 0 Spot Ankara-Golbasi D7 27 Apr 02 3 7 Line 5000 Ankara-K. hamam D7 27 Apr 02 1 4 4 Spot Ankara-Mogan D7 27 Apr 02 3 8 Line 9000 Antalya-Seydisehir G6 27 Apr 02 3 3 Line 9000 Izmir-Cigli El 27 Apr 02 1 3 3 Spot Izmir-Gediz El 27 Apr 02 1 2 4 Spot Konya-Seydisehir F6 27 Apr 02 2 2 Line 7000 Bursa-Uluabat C3 28 Apr 02 6 6 80 Spot Kars-Susuz C18 28 Apr 02 4 68 Line 2000 Ardahan-Posof, Georgian Bord. B17 29 Apr 02 4 4 Line 2000 Kars-Damal C18 29 Apr 02 1 2 Line 3000 Isparta-Kovali-Egirdir F4 2 May 02 3 4 49 Spot Kayse ri-Kumarli ElO 2 May 02 1 0 0 Spot Balikesir-Kazdagi D1 4 May 02 3 0 0 Spot Bolu-Mengen C6 4 May 02 0 0 Line 6000 Bursa-Uluabat-Golyazi C3 4 May 02 1 3 3 Spot Eskisehir-Balikdami D6 4 May 02 1 4 55 Spot Isparta-Atabey F4 4 May 02 1 0 0 Spot Edirne-Doyran B1 5 May 02 1 5 12 Spot Izmir-Aliaga El 5 May 02 3 1 2 Spot Sanliurfa-Bire cik F12 6 May 02 1 0 0 Spot

Ankara-ODTU D7 9 May 02 1 1 1 Spot Isparta-Kizildag F4 10 May 02 1 2 5 Spot Istanbul B3 10 May 02 4 2 16 Spot Adana-Yumurtalik GIO 11 May 02 1 2 2 Spot Konya-Kulu D8 11 May 02 4 7 Line 4000 Samsun-Cernek Bll 11 May 02 4 16 Line 1000 Istanbul-Arboretum B3 12 May 02 2 0 0 Spot Izmir-Gediz El 12 May 02 1 1 1 Spot Ankara-Cubuk C8 15 May 02 3 2 6 Spot Izmir-Yenifoca El 15 May 02 1 2 2 Spot Bursa-Uluabat C3 16 May 02 5 1 3 Spot Tunceli-Ovacik, Copluk D14 17 May 02 3 63 Line 1000 Ankara-Mogan D7 18 May 02 2 10 Line 9000 Konya-Kulu D8 18 May 02 3 5 Line 4000

Istanbul-Buyukada C3 19 May 02 2 1 1 Spot Ankara-Altinpark D7 20 May 02 1 0 0 Spot 52 Turan VoL. 39, No. 1

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species OF Raptors Type (m)

Bursa-Uluabat C3 21 May 02 1 1 1 Spot Ankara-ODTU D7 23 May 02 1 2 3 Spot Ankara-Bilkent D7 24 May 02 2 1 1 Spot Antalya-Bogazkent G5 25 May 02 1 1 1 Spot Kocaeli C4 25 May 02 1 0 0 Spot Konya-Kulu D8 25 May 02 0 0 Line 4000 Ankara-Mogan D7 26 May 02 2 6 Line 9000 Istanbul-Heybeliada C3 26 May 02 1 2 3 Spot

Ankara-Camkoru C7 1 Jun 02 1 2 7 Line 2500 Artvin-Savsat B17 6Jun 02 4 17 Line 7000 Trabzon-Sumela B14 6 Jun 02 1 0 0 Spot Izmir-Inciralti El 8 Jun 02 2 0 0 Spot Samsun-Kizilirmak BIO 8 Jun 02 3 4 Line 2200 Sivas-Divrigi D13 8 Jun 02 2 2 Line 5000 Sivas-Divrigi, Degirmentasi D13 8 Jun 02 2 1 1 Spot Sivas-Golova Dll 8 Jun 02 1 0 0 Spot Sivas-Sarkisla Dll 9 Jun 02 1 3 4 Spot Sivas-Yildizeli D12 9 Jun 02 1 2 2 Spot Ankara-K. hamam C7 10 Jun 02 1 3 3 Spot Bolu-Gerede C6 10 Jun 02 1 1 1 Spot Tunceli-Munzur D14 11 Jun 02 2 3 Line 5000 Tunceli-Mercan D14 12 Jun 02 2 3 6 Spot Ankara-Beypazari C7 15 Jun 02 1 5 18 Spot Ankara-Kurtbogazi D7 15 Jun 02 1 1 1 Spot Konya-Kulu D8 15 Jun 02 3 7 Line 4000 Bursa-Uluabat C3 16 Jun 02 2 1 14 Spot Denizli-Acigol F4 16 Jun 02 1 0 0 Spot Ankara-ODTU D7 20 Jun 02 1 1 3 Spot Konya-Kulu D8 21 Jun 02 3 6 Line 4000 Bursa-Uludag C4 22 Jun 02 1 1 1 Spot Manisa-Spil E2 22 Jun 02 1 3 Line 2000 Bursa-Uludag C4 23 Jun 02 2 1 1 Spot Corum-Ayarik C9 28 Jun 02 1 0 0 Spot Istanbul-Halkali B3 28 Jun 02 1 1 1 Spot Izmir-Karaburun El 29 Jun 02 1 3 5 Spot Kayseri-Palas ElO 29 Jun 02 1 2 2 Spot

Bursa-Kocacay C3 1 Jul 02 1 2 2 Spot

Kayseri-Engir ElO 1 Jul 02 1 2 5 Spot

Kayseri-Palas ElO 1 Jul 02 1 2 5 Spot Trabzon-Sivrikaya B14 3 Jul 02 1 3 4 Spot Bolu-Abant C6 6 Jul 02 1 0 0 Spot Canakkale-Bozcaada Cl 6 Jul 02 1 1 Line 5000 Kayseri-Hisarcik ElO 6 Jul 02 1 2 2 Spot Bursa-Uluabat C3 7 Jul 02 2 1 2 Spot Mugla; Marmaris-Datca G2 7 Jul 02 4 8 Line 2000 Yozgat D9 10 Jul 02 1 1 Line 2000 Artvin-Merkez B16 13 Jul 02 3 9 Line 9000 Karabuk-Safranbolu B7 13 Jul 02 3 1 6 Spot Tunceli-Ovacik-Gozeler D14 16 Jul 02 3 1 2 Spot Istanbul-Buyukcekmece B3 27 Jul 02 1 1 1 Spot Balikesir-Edremit D1 3 Aug 02 3 1 1 Spot Agri-Ararat D18 9 Aug 02 2 3 3 Spot March 2005 Status of Diurnal Raptors in Turkey 53

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species of Raptors Type (m)

Mugla-K. Gol G2 14 Aug 02 1 1 1 Spot

Balikesir-Kazdagi DI 15 Aug 02 1 3 14 Spot Balikesir-Kocacay C2 15 Aug 02 2 2 2 Spot Mugla-Sarigerme F2 15 Aug 02 1 0 0 Spot Canakkale-Gokceada Cl 17 Aug 02 0 0 Line 4000

Mugla-Kalkan G2 17 Aug 02 1 0 0 Spot Burdur Lake E5 19 Aug 02 1 0 0 Spot Corum-Golyazi C9 27 Aug 02 1 2 2 Spot

Bolu-Gerede C6 30 Aug 02 1 3 9 Spot

Kastamonu-Pinarbasi B9 30 Aug 02 1 1 2 Spot

Kastamonu-Pinarbasi B9 31 aug 02 1 6 7 Spot

Karabuk B7 1 Sep 02 1 1 2 Spot

Ankara-K. hamam C7 2 Sep 02 1 4 13 Spot

Erzurum-Aydintepe C16 5 Sep 02 1 1 5 Spot Ankara-K. hamam C7 9 Sep 02 3 7 12 Spot

Bursa-Niliifer C3 9 Sep 02 1 0 0 Spot

Ankara-ODTU D7 11 Sep 02 1 6 15 Spot

Bursa-Kocacay C3 11 Sep 02 1 3 10 Spot Bursa-Niliifer C3 11 Sep 02 2 0 0 Spot Kayseri-Hisarcik ElO 12 Sep 02 1 0 0 Spot

Ankara-K. hamam C7 13 Sep 02 1 4 13 Spot Istanbul-Riva B4 14 Sep 02 2 5 9 Spot

Edirne-Doyran BI 15 Sep 02 1 4 4 Spot Istanbul-Catalca-Gokceali B3 16 Sep 02 0 0 Line 2400 Istanbul-Terkos B3 16 Sep 02 2 8 11 Spot Hatay-Subasi GIO 19 Sep 02 1 9 362 Spot

Hatay-Sinanli GIO 20 Sep 02 1 9 1528 Spot Istanbul-Riva B4 20 Sep 02 2 5 10 Spot Istanbul-Buyukcekmece B3 21 Sep 02 1 0 0 Spot

Ankara-K. hamam C7 23 Sep 02 1 5 7 Spot Ankara-K. hamam C7 23 Sep 02 1 5 11 Spot

Hatay-Subasi GIO 26 Sep 02 1 7 122 Spot Tokat-Kaz Lake Cll 26 Sep 02 6 17 Spot 1200 Hatay-Samandag GIO 27 Sep 02 2 3 7 Spot Istanbul-Buyukcekmece B3 27 Sep 02 2 4 6 Spot Konya-Kulu D8 28 Sep 02 3 5 Line 4000 Tokat-Kaz Lake Cll 28 Sep 02 7 12 Spot 1200 Ankara-K. hamam C7 29 Sep 02 2 7 92 Spot

Mersin-Kargipinari G7 29 Sep 02 1 0 0 Spot Konya-Kulu D8 5 Sep 02 3 6 Line 4000

Denizli-Acigol E4 6 Oct 02 1 1 3 Spot

Antalya-Belek G5 7 Oct 02 1 0 0 Spot Izmir-Kampus El 8 Oct 02 1 2 2 Spot

Istanbul-Buyukcekmece B3 12 Oct 02 1 0 0 Spot

Ankara-Gudul C7 13 Oct 02 1 3 4 Spot Istanbul-Buyukcekmece B3 13 Oct 02 1 0 0 Spot Istanbul-Catalca B3 13 Oct 02 2 2 101 Spot

Istanbul-Terkos B3 13 Oct 02 1 7 13 Spot

Ankara-K. hamam C7 14 Oct 02 1 9 Line 10000 Istanbul-Maslak B3 14 Oct 02 1 0 0 Spot Mus E16 18 Oct 02 3 2 14 Spot 54 Turan VoL. 39, No. 1

Appendix. Continued.

Observa- Number Number Observa- Transect tion Sampling OF Spot OF Raptor Number tion Distance Province/District Grid Date Counts Species OF Raptors Type (m)

Bingol-Karliova D15 19 Oct 02 2 27 Line 2000 Mus-Bulanik E16 19 Oct 02 2 1 1 Spot Ankara-Mogan D7 20 Oct 02 5 14 Line 9000 Sanliurfa-Ceylanpinar G14 20 Oct 02 6 6 137 Spot Nigde-Aladaglar E9 29 Oct 02 4 3 8 Spot Ardahan-Hanak C17 12 Nov 02 4 4 Line 4500 Ardahan-Posof B17 13 Nov 02 2 4 Line 7000 Ardahan-Posof BlV 14 Nov 02 1 2 Line 5000 Kars CIS 15 Nov 02 1 1 1 Line 2000 Kars CIS 15 Nov 02 0 0 Line 6000 Kars-Selim CIS 15 Nov 02 1 4 5 Spot Izmir-Inciralti El 16 Nov 02 2 0 0 Spot Kars-Sarikamis CIS 16 Nov 02 2 2 3 Spot Ankara-Mogan D7 17 Nov 02 4 4 Line 9000 Erzurum-Hasankeyf D15 17 Nov 02 1 1 Line 5000 Erzurum-Pasinler C15 17 Nov 02 1 0 0 Line 3000 Izmir-Gediz El 17 Nov 02 2 5 5 Spot Kayseri-Sultan Sazligi ElO 20 Nov 02 3 4 4 Spot Sanliurfa-Birecik E12 21 Nov 02 1 0 0 Spot Samsun-19 Mayis Bll 23 Nov 02 1 0 0 Spot Samsun-Atakum Bll 24 Nov 02 1 0 0 Spot Izmir-Aliaga El 30 Nov 02 1 5 5 Spot Samsun-Dogupark, Mert Bll 30 Nov 02 2 0 0 Spot Tunceli-Ovacik D14 30 Nov 02 1 1 Line 5000 Kirsehir-Seyfe D9 30 Nov 02 3 9 Line 2500 Kirsehir-Seyfe D9 30 Nov 02 3 4 Line 1500 Izmir-Cakalburnu El 1 Dec 02 1 0 0 Spot Izmir-Gediz El 1 Dec 02 1 6 8 Spot Sanliurfa-Birecik El 2 1 Dec 02 1 0 0 Spot K Maras-Andirin Ell 2 Dec 02 2 2 Line 2000 K Maras-Andirin Ell 3 Dec 02 1 1 Line 5000 Ankara-Nallihan C7 5 Dec 02 1 2 2 Spot Ankara-Nallihan, Sariyar C7 6 Dec 02 1 0 0 Spot Ankara-Kazan, Ovacay C7 7 Dec 02 2 4 6 Spot Samsun-Kizilirmak BIO 7 Dec 02 1 3 15 Line 2200 Konya-Kulu D8 10 Dec 02 4 7 Line 4000 Konya-Kulu D8 11 Dec 02 2 4 Line 4000

Ankara-Bilken t D7 21 Dec 02 2 2 2 Spot Edirne-Doyran B1 21 Dec 02 2 3 33 Spot Istanbul-K. Cekmece B3 21 Dec 02 2 1 1 Spot Samsun-Dogupark Bll 21 Dec 02 1 0 0 Spot Samsun-Kizilirmak BIO 22 Dec 02 4 26 Line 2200 Izmir-Gediz El 29 Dec 02 1 8 12 Spot Samsun-Atakum Bll 29 Dec 02 0 0 Line 6000 Balikesir-Ayvalik D1 30 Dec 02 3 3 11 Spot Izmir-Gediz El 31 Dec 02 6 0 0 Spot N= 499 N= 162 X = 1.47 X - 5097 5 Short Communications

Seasonal Diet oe the Aplomado Falcon (Falco femoralis) in an Agricultural Area of Araucania, Southern Chile

Ricardo A. Figueroa Rojas^ and Ema Soraya Corales Stappung Estudios para la Conservacion y Mango de la Vida Silvestre Consultores, Blanco Encalada 350, Chilian, Chile

Key Words: Aplomado Falcon', Falco femoralis; diet, agri- cania region, southern Chile. The landscape is com- cultural areas; Chile. prised mainly of wheat and oat crops, scattered pasture and sedge-rush (Carex-Juncus spp.) marshes, small plantations of nonnative Pinus spp. and Eucalyptus spp., and The Aplomado Falcon (Falco femoralis) is distributed remnants of the native southern beech (Nothofagus spp.) from southwestern United States to Tierra del Fuego Isla forest. The climate is moist-temperate with a Mediterra- Grande in southern Argentina and Chile. Aplomados in- nean influence (di Castri and Hajek 1976). Mean annual habit open areas such as savannas, desert grasslands, An- rainfall and temperature are 1400 mm and 12°C, respec- steppes, tree-lined dean and Patagonian and pastures, tively. from coastal plains up to 4000 m in the Andes (Brown From August (austral winter) to December (austral and Amadon 1968, de la Pena and Rumboll 1998). In spring-summer) 1997, we collected 65 pellets under the United States, the Aplomado Falcon is listed as en- trees and fence posts used as pluck sites by at least one dangered (Shull 1986) due to the historical modification pair of Aplomado Falcons. We collected 40 pellets during winter 25 during spring-summer. prey of its habitats and cumulative effects of DDT (Kiff et al. and A few remains also collected beneath sites the 1980, Hector 1987). In contrast, the Chilean population were pluck during spring-summer period. Although pellets could be con- may be increasing. Forest conversion to agricultural lands fused with those of the sympatric Cinereous Harrier (Cir- have increased hunting habitat and prey availability for cus cinereus) or American Kestrel (Falco sparverius), we this species (Jaksic and Jimenez 1986). Nonetheless, the only saw Aplomado Falcons at the collection sites during Falcon is rare in southern Aplomado Chile (Jaksic and our study. Perches identified as those of Cinereous Har- Jimenez 1986) and it is protected legally (Republica de riers and American Kestrels were located away from (1.0- Chile 1996, 1998). 1.5 km) known Aplomado Falcon pluck sites. In addition,

The biology of the Aplomado Falcon is little known. Aplomado Falcons are aggressive toward other raptors Breeding biology, survival, movements, and habitat use (Hector 2000, Brown et al. 2003).

have recently been reported (Perez et al. 1996, Montoya Avian prey were identified mainly on the basis of feathers, using two complementary methods: microscopic et al. 1997). Studies on Aplomado Falcon summer diet analysis of feather structures such as nodes and barbules have been conducted in northern Mexico (Hector 1981, (Reyes 1992), and a comparison of feather coloration 1985), northern Chile (Jimenez 1993), and southeastern patterns with voucher specimens deposited in the Zool- Argentina (Bo 1999). Some recent anecdotal descrip- ogy Department of the Universidad Austral of Chile at tions of predation on crayfish (Combarus diogenes; Clark Valdivia. We assumed that species identified in a pellet et al. 1989), Spotted Tinamous (Nothura maculosa; Silveira represented only one individual. Small mammals were et al. 1997), and lizards (Liolaemus lineomaculatus; Trejo identified and quantified on the basis of skulls or denti- et al. 2003) have also been published. Piracy also has tion following Pearson (1995). Insects were identified been documented as an important foraging method for and quantified by head capsules or elytra following Pena

obtaining mammal prey from other raptors (Brown et al. (1986). We identified prey items to the finest possible 2003). However, seasonal differences in diet have not taxonomic category. Biomass contribution was estimated been described. Here, we report the seasonal diet of following Marti (1987). Masses for small mammal and avian prey followed Figueroa and Corales (1999). Insect Aplomado Falcons and correlate it with prey abundance masses were based on the authors’ unpublished data. We in the Araucanian agricultural area in southern Chile. assumed that unidentified prey masses were similar to the Study Area and Methods mean mass of the most closely related identified taxon. Concurrent to the collection of pellets, we evaluated Our study area was the Tricauco Farm (200 ha), 6 km bird and small mammal prey abundance in the field. We south of Traiguen city (38°14'S, 72°38'W) in the Arau- estimated bird abundance using parallel, fixed-band (2000 m long, 100 m wide) line transects (Bibby et al. ^ Email address: [email protected] 1993) placed 400 m apart in the hunting areas of falcons.

55 56 Short Communications VoL. 39, No. 1

Table 1 . Diet of the Aplomado Falcon (Falco femoralis) determined from pellets in an agricultural area of the Ar- aucania region, southern Chile.

Winter Spring-Summer Annual

Percent Percent Percent Mass'^ Frequen- Percent Frequen- Percent Frequen- Percent

Prey Species (g) Diet'^ cy Biomass cy Biomass cy Biomass

Mammals 42.5 15.9 2.4 0.7 27.8 9.7 Rodentia

Abrothrix olivaceus 23 O 12.3 4.6 0 0 7.9 2.7 Oligoryzomys longicaudatus 26 G (F) 6.9 2.9 0 0 4.3 1.7 Mus domesticus 21 O 6.9 2.3 0 0 4.3 1.4 Unidentified rodents 23 16.4 6.1 2.4 0.7 11.3 3.9

Birds 57.5 84.1 88.1 99.2 68.7 90.2 Columbiformes

Columba araucaria 300 F (G) 2.7 13.3 4.7 19.2 3.5 15.7 Zenaida auriculata 137 G 13.7 30.4 14.4 26.3 13.9 28.7

Passeriformes

Turdus falcklandii 90 F (I) 17.8 26.0 23.8 28.8 20.0 27.1

Antbus correndera 22 I 0 0 4.7 1.4 1.7 0.6 Sicalis luteiventris 16 G 12.3 3.2 23.8 5.1 16.5 4.0 Zonotrichia capensis 22 G (I) 1.4 0.5 0 0 0.9 0.3

Sturnella loyca 96 I (G) 4.1 6.4 12.0 15.3 7.0 10.0 Unidentified Passeriformes 49 5.5 4.3 4.7 3.1 5.2 3.8

Insects orders: 0 0 9.5 'J’c 3.5 Tc

Odonata 1.0 0 0 2.4 0.9 Tc Coleoptera 0.5 0 0 7.1 2.6 TC Total prey items 73 42 115 Total biomass 4508 3130 7638 Total pellets 40 25 65

Mass estimates from Figueroa and Corales (1999), except for A. correndera and Z capensis (unpubl. data). Determined from Munia (1996) for small mammals and Estades and Temple (1999) for birds; F = frugivores, G = granivores, I =

insectivores, O = omnivores. Secondary diet is given in parentheses. T = trace; values less than 1%.

Eight line transects were established during winter and estimate GMW. Differences among GMW were analyzed three during spring-summer. The abundance of small using t-tests (Fowler and Cohen 1986). To determine mammals was evaluated by trapping transects (Call 1986) whether falcons took vertebrate prey selectively or op- using medium Sherman live traps (10-15 m apart) portunistically, we compared frequency distribution of placed in unaltered pasture and marshes. Three 10-trap prey in pellets versus prey abundance in the field using transects were established in pasture during winter and Spearman’s rank correlation as recommended by Jaksic three in pasture and two in marshes during spring-sum- (1979) for a comparison between prey consumption and mer, and these were sampled for 5 nights. Thus, total availability. Because of the small sample size for each sea- effort was 351 trap-nights (nonfunctional traps were dis- son, we combined results of the winter and spring-sum- counted) . mer diet for correlations. Seasonal changes between proportions in different prey taxa in diet were evaluated with chi-square tests us- Results ing contingency tables (Fowler and Cohen 1986). Only Whole pellets averaged 27.3 ±1.3 mm length X 13.3 vertebrate prey were included for analysis; contribution ± 0.5 mm width and had a mean dry weight of 0.9 ± of insects was insignihcant. Geometric mean weight of 0.08 (x ± SE, = 36). In total, we identihed 115 prey prey (Marti 1987) was calculated as follows: GMW = an- g N tilog (Sn^logtc/Snj), where was the number of individ- items in the pellets including seven bird species, three uals of the ith species and w, was the mean weight. Only rodent species, and three insect orders (Table 1 ) . By both prey items identified to species level were included to number and biomass, birds were the most common prey ,

March 2005 Short Communications 57

Table 2. Relative bird abundanee estimated by the line-transect method during 1997 in an agricultural field in Tricauco, 7\raucania region, southern Chile. Values are pooled results of the winter and spring-summer surveys.

Percent Individuals Species (%)

Eared Dove {Zenaida auriculata) 2.7 Black-faced Ibis {Theristicus melanopis) 1.8 California Quail (Callipepla californica) 2.1 Southern Lapwing (Vanellus chilensis) 20.0 Austral Parakeet {Enicognathus ferrugineus) 3.0 Dark-faced Ground-Tyrant {Muscisaxicola macloviana) 2.0 House Wren {Troglodytes aedon) 3.3 Austral Thrush {Turdus falcklandii) 11.5 Correndera Pipit (Anthus correndera) 4.2 Grassland Yellow-Finch {Sicalis luteiventris) 22.5 Rufous-collared Sparrow {Zonotrichia capensis) 7.6 Yellow-winged Blackbird {Agelaius thilius) 3.2 Long-tailed Meadowlark {Sturnella loyca) 4.1 Common Diuca-Finch {Diuca diuca) 4.3

Black-chinned Siskin ( Carduelis barbata) 3.0 Other birds'^ 4.7 Total individuals 1782

® Includes all bird species that individually accounted for less than 1% in abundance.

of the Aplomado Falcon (Table 1). Passerines were the prising 33 species. The most numerous species were the group of birds most frequently found in pellets, with Aus- Grassland Yellow-Finch, Southern Lapwing {Vanellus chi-

tral Thrushes {Turdus falcklandii) and Grassland Yellow- femw) , Austral Thrush and Rufous-collared Sparrow {Zon-

Finches {Sicalis luteiventris) being the most common prey otrichia capensis-. Table 2) - More birds were observed dur- species (Table 1). By biomass, the Austral Thrush and ing winter (993 birds/km^) than spring-summer (482 Eared Dove {Zenaida auriculata) were the most important birds/km^). We captured 43 rodents comprising seven avian prey both during winter and spring-summer. Ro- species. By number, the most abundant species were the dents were an important part of the winter and overall olivaceus field mouse, long-tailed rice rat {Oligoryzomys diet with olivaceus field mice {Abrothrix olivaceus) being longicaudatus) and house mouse {Mus domesticus-. Fig. 1). the most frequent (Table 1). Insects were negligible both Rodent captures declined from winter (22 rodents/100 by number and biomass. trap nights) to spring-summer (5 rodents/ 100 trap Because of small sample size and uncertainty as to how nights). much of each item was consumed, we did not use prey Only 21.2% of the potential bird prey were found in remains to quantify diet. However, feather remains con- the pellets (7 out of 33). Spearman rank correlation was firmed that the Austral Thrush and Eared Dove were the = 0.42 (P < 0.05, N = 33) when all bird prey were most common prey of the Aplomado Falcon. In addition, considered; and r^ = 0.72 (P < 0.01, N = 19) when pas- we found elytra {N = 40) of the cerambycid Acanthinodera serines alone were considered. Although we made no sta- cummingi indicating 20 individuals. tistical correlation for rodents because low numbers of More birds and less rodents were consumed during species were identified in the diet, their proportions were = spring-summer as compared to the winter season (x^ in close agreement with those observed in the field (Fig.

17.4, P < 0.001; Table 1). Proportions of Columbiformes 1 ). and Passeriformes remained similar between seasons (x^ Discussion = 0.2, P > 0.05). Global GMW were 42.0 ± 9.1 g for all prey, 51.8 ± 10.3 g for all vertebrate prey, and 63.9 ± As in previous studies (Hector 1985, Jimenez 1993, 14.2 g for birds alone. No seasonal differences were de- Montoya et al. 1997, B6 1999), the Aplomado Falcon in tected in GMW for all prey combined (48.3 ± 6.1 g for Tricauco was essentially an avian predator. Our study was = winter and 37.0 ± 5.5 g for spring-summer; ^ —1.3, most comparable to Hector (1985) and B6 (1999) be- P > 0.05) or for vertebrate prey (48.3 ± 6.1 g for winter cause it was also conducted in agricultural areas. Similar and 58.8 ± 5.6 g for spring-summer; % = 0.6, P> 0.05). to our results, both of these studies found that during For the year, we counted 1782 non-raptor birds com- the breeding season passerines and doves were the most 58 Short Communications VoL. 39, No. 1

50 its abundance), especially for passerine birds and rodents. However, the results also suggested that nonpas- serine-avian prey may not he taken according to their abundance. Aplomado Falcons caught proportionally more doves than passerines. The Eared Dove ranked third by number in the diet, but twelfth in the field surveys. Its abundance in the diet may be explained in two ways. First, Eared Doves have greater body mass and, therefore, provide greater energetic benefits. Second, doves in large flocks frequently used cultivated fields during the winter when cereal seeds were more available (Bucher and Orueta 1977), possibly making this species more vulnerable to predation. In addition, Aplomado Aoli Olon Mdom Alon Rnor Lmic Pdar Falcons may have captured doves when they were roost- Species ing in trees (Hector 1986). The Aplomado Falcon’s apparent selection of Eared Figure 1. Comparison between the proportion of ro- Doves was further indicated by the fact that no Southern dent prey in the Aplomado Falcon’s diet versus the rel- Lapwings (body mass = 270 g) were found in the falcon’s ative abundance in the field estimated by live-trapping diet. The Southern Lapwing is a conspicuous ground- during 1997 in an agricultural field in Tricauco, Arau- dwelling bird and was the second most abundant species canfa region, southern Chile. Graph shows the pooled in the field (356 individuals, 20% in number). We sug- results of the winter and spring—summer diet and field gest that their aggressive defensive behaviour prevented trapping. Aoli = Abrothrix olivaceus, Olon = Oligoryzomys the falcons from preying upon lapwings. When menaced longicaudatus, Mdom = Mus domesticus, Alon = A. longi- by a potential predator, Southern Lapwings simulate at- ptlis, Rnor = Rattus norvegicus, Lmic = Loxodontomys mi- tacks by exhibiting their wing-spurs and emitting strident cropus, Pdar = Phyllotis darwini. vocalizations (Walters 1990). Regarding passerine prey, the rate of consumption of important prey for Aplomado Falcons. The small number Austral Thrushes and Grassland Yellow-Finches were con- of bird species observed in the diet in Tricauco com- sistent with their abundance in the field, but was proba- pared to those observed during surveys in the field (Ta- bly accentuated by their conspicuousness. Similar to ble 2) was probably a result of small sample size of pellets Eared Doves, both species moved actively in large flocks analyzed. when searching for food on cultived fields. Although the The importance of birds in the Aplomado Falcon’s diet Grassland Yellow-Finch was the smallest passerine avail- was seasonally consistent, suggesting that birds are pre- able (16 g), its abundance in open fields may have com- ferred prey in spite of variability in temporal abundance pensated for its small caloric value. Like Jimenez (1993), in the field. The seasonal proportion of rodents in the we found that Aplomado Falcons generally took more Aplomado Falcon’s diet in Tricauco was in close agree- seed-eating than insectivorous birds (6:1; see Table 1) ment with the results of the rodent trapping (Fig. 1). Thus, Aplomado Falcons may be less affected by organ- Murua and Gonzalez (1986) documented a similar oscil- ochlorine pesticides in the agricultural fields of Chile lation for a rodent population in prairie-scrublands of than in Mexico (Kiff et al. 1980). southern Chile. Our data suggests that Aplomado Fal- Our examination of other vegetative-cover types sug- cons in Tricauco could respond opportunistically to the gested that agricultural fields offer a wide variety of ap- availability of rodents that varies seasonally. It is possible propriately-sized prey of which Aplomado Falcons can ex- that some rodent prey were taken by pirating from other ploit selectively or opportunistically in southern Chile. raptors, as documented for Aplomado Falcons in south- However, our inferences must be limited because of the ern Texas and northern Mexico (Brown et al. 2003), but small sample size of pellets and the restricted study area we did not witness piracy in Tricauco. considered. More data using appropriate methods to The GMW of all prey taken during breeding season in study dietary and foraging habits of Aplomado Falcons Tricauco was greater than those reported by Hector should clarify the relationships suggested by our study.

(1981) in Mexico (23.8 g) and Bo (1999) in Argentina (25 g); this result was likely due to the higher incidence DIETA ESTA.SIONAL DE FALCO FEMORALIS EN UN ArEA of larger prey in our study area. It is also possible that AgrIcola de Araucania, Sur de Chile higher GMW for Tricauco was an artifact of the relatively small numbers of pellets collected during spring-sum- Resumen.—La dieta del halcon Falco femoralis fue cuan- mer. In general, our results suggested that Aplomado Fal- tificada sobre la base de 65 regurgitados colectados dur- cons consumed most of their prey opportunistically rath- ante 1997 en un area agricola del sur de Chile. Las aves er than selectively (i.e., they took prey in proportion to fueron el nucleo de la dieta (58-88% por numero, 84— March 2005 Short Communications 59

99% por biomasa), siendo Turdus falcklandii, Sicalis luteiv- de la Pena, M. and M. Rumboll. 1998. Birds of southern entris y Zenaida auriculata las presas mas importantes. Los South America and Antarctica. Harper Collins Pub- roedores fueron importantes en la dieta invernal (43% lisher Ltd., London, U.K. por numero, 16% por biomasa), pero disminuyeron no- di Castri, F. and E. Hajek. 1976. Bioclimatologia de toriamente en primavera-verano, coincidiendo con la Chile. Univ. Catolica de Chile, Santiago, Chile. abundancia estacional de roedores en el campo. El peso Estades, C.F. and S.A. Temple. 1999. Deciduous-forest medio geometrico fue 42.0 ± 9.1 g para todas las presas bird communities in a fragmented landscape domi- y 51.8 ± 10.3 g para las presas vertebradas. Estos valores nated by exotic pine plantation. Ecol. Appl. 9:573-585. son mas altos a los reportados por otros autores y seria Figueroa, R.A. and E.S. Corales. 1999. Food habits of una consecuencia de la mayor incidencia de presas gran- the Cinereous Harriers {Circus cinereus) in the Arau- cania, des en nuestra area de estudio. El halcon perdiguero southern Chile. J. Raptor Res. 33:264-267. consuraio una importante fraccion de sus aves presa de Fowler, J. and L. Cohen. 1986. Statistics for ornitholo- acuerdo a nuestras estimaciones de abundancia en el gist. British Trust for Ornithology, Norfolk, U.K. campo (r^ = 0.42, P< 0.05). Las tortolas, sin embargo, Hector, D.P. 1981. The habitat, diet, and foraging be- fueron consumidas en mayor proporcion que los paseri- havior of the Aplomado Falcon, Ealco femoralis (Tem- nos. Esto sugiere que el halcon perdiguero en Tricauco minck). M.S. thesis, Oklahoma State Univ., Stillwater, se comportaria como un depredador parcialmente selec- OK U.S.A. tive. . 1985. The diet of the Aplomado Falcon {Ealco [Traduccion de los autores] femoralis) in eastern Mexico. Condor 87:336—342.

. 1986. Cooperative hunting and its relationship to Acknowledgments foraging success and prey size in an avian predator. We thank the Zenhder Stappung family for permission Ethology 73:247-257. to work on their lands and are especially grateful to Olga . 1987. The decline of the Aplomado Falcon in the Stappung for partially funding this study and to Lilian United States. Am. Birds 41:381-389. Stappung for logistical support. Roberto Schlatter kindly . 2000. Aplomado Falcon {Falco femoralis). In A permitted access to collections in the Departamento de Poole and F. Gill [Eds.], The birds of North America, Zoologia de la Universidad Austral in Valdivia. Diane No. 549. The Birds of North America, Inc., Washing- Haughney helped us with the English revision. Cogent ton, DC U.S.A. and enlightening suggestions by Ana Trejo, David Ellis, Angel Montoya, Michael Goldstein, and an anonymous Jaksic, F.M. 1979. Tecnicas estadisticas simples para ev- reviewer helped to improve this paper substantially. This aluar selectividad dietaria en Strigiformes. Medio Am- paper is a product of the Wildlife in Agricultural Land- biente 4:114-118. scape project financed by private funds. AND H.E. Braker. 1983. Food-niche relationships and guild structure of diurnal birds of prey: compe- Literature Cited tition versus opportunism. Can. f Zool. 61:2230—2241. Bibby, C., N. Burges, and D. Hill. 1993. Bird census AND J.E. Jimenez. 1986. The conservation status of techniques. Academic Press, London, U.K. raptors in Chile. Birds Prey Bull. 3:95-104. B6, M.S. 1999. Dieta del halcon plomizo {Falco femoralis) Jimenez, J.E. 1993. Notes on diet of the Aplomado Falcon en el sudeste de la Provincia de Buenos Aires, Argen- {Falco femoralis) in northcentral Chile./. Raptor Res. 27: tina. Ornitol. Neotrop. 10:95-99. 161-163. Brown, L.H. and D. Amadon. 1968. Eagles, hawks, and Kief, L.F., D.P. Peakall, and D.P. Hector. 1980. Eggshell

falcons of the world. Vol. 1. Country Life Books, Lon- thinning and organochlorine residues in Bat and don, U.K. Aplomado falcons in Mexico. Proceedings from the

Brown, J.L., A.B. Montoya, E.J. Gott, and M. Curtl XVII International Ornithological Congress (1978), 2003. Piracy as an important foraging method of Berlin, Germany. Aplomado Falcons in southern Texas and northern Krebs, G.J. 1989. Ecological methodology. Harper Collins Mexico. Wibon Bull. 115:357-359. Publisher, Inc., New York, NYU.S.A. Bucher, E.H. and A. Orueta. 1977. Ecologia de la re- Marti, C. 1987. Raptor food habits studies. Pages 67-79 produccion de la paloma Zenaida auriculata. Ecosur4: in B.A. Pendleton, B.A. Millsap, K.W. Cline, and D.M. 157-185. Bird [Eds.], Raptor management techniques manual. Call, M. 1986. Rodents and insectivores. Pages 429-452 National Wildlife Federation Technical Series 10,

in A.Y. Cooperrider, R.J. Boyd, and H.R. Stuart [Eds.], Washington, DC U.S.A. Inventory and monitoring of wildlife habitat. U.S. De- Montoya, A., P. Zwank, and M. Cardenas. 1997. Breed- partment of the Interior. Bureau of Land Manage- ing biology of Aplomado Falcon in desert grasslands ment Service Center, Denver, CO U.S.A. of Chihuahua, Mexico./. Field Ornithol. 68:123-135. Clark, W.S., P.H. Bloom, and L.W. Oliphant. 1989. Murua, R.E. 1996. Comunidades de mamiferos del Aplomado Falcon steals prey from Little Blue Heron. bosque templado de Chile. Pages 113-133 mJ.J. Ar- [Eds.], J. Field Ornithol. 60:380-381. mesto, C. Villagran, and M.T.K. Arroyo Ecol- , ,

60 Short Communications VoL. 39, No. 1

ogia de los bosques natives de Chile. Editorial Univ., Reyes, C. 1992. Clave para la identificacion de los orde- Santiago, Chile. nes de aves chilenas: microestructura de los nodes de AND L.A. Gonzalez. 1986. Regulation of numbers las barbulas. M.S. thesis, Univ. Lagos, Osorno, Chile in two neotropical rodent species in southern Chile. Shull, A.M. 1986. Final rule; listing of the Aplomado Rev. Chil. Hist. Nat. 59:193-200. Falcon as endangered. U.S. Fish and Wildlife Service, Pearson, O. 1995. Annotated keys for identifying small Federal Register 51:6686-6690, Washington, DC mammals living in or near Nahuel Huapi National U.S.A. Park or Lanin National Park, southern Argentina. SiLVEiRA, L., A.T.A. Jacomo, F.H.G. Rodrigues, and P.G. Mastozool. Neotrop. 2:99-148. Crawshaw, Jr. 1997. Hunting association between the Pena, L. 1986. Introduccion a los insectos de Chile. Ed- Aplomado Falcon {Falcofemoralis) and the maned wolf itorial Univ., Santiago, Chile. (Chrysocyon brachyurus) in Emas National Park, central

Perez, C.J., P.J. Zwank, and D.W. Smith. 1996. Survival, Brazil. Condor 99:201—202. movements, and habitat use of Aplomado Falcons re- Trejo, A., S. Seijas, and M. Sahores. 2003. Liolaemus h- leased in southern Texas./. Raptor Res. 27:175-182. weoTnacit/aim predation. Herpetol. Rev. 34:145.

Republica de Chile. 1996. Ley de Caza N- 19473: Diario Walters, J.R. 1990. Anti-predatory behavior of lapwings’ oficial, 4 de septiembre de 1996. Ministerio de Agri- field evidence of discriminate abilities. Wilson Bull cultura, Santiago, Chile. 102:49-70.

. 1998. Reglamento de la Ley de Caza, D.S. N“ 5, Diario Oficial, 7 de diciembre de 1998. Ministerio de Received 13 February 2004; accepted 6 September 2004

Agricultura, Santiago, Chile. Associate Editor: Michael 1. Goldstein

Mesostigmatic Mites (Acari: Mesostigmata) in White-tailed Sea Eagle Nests {Haliaeetus60- albicilla)

DariuszJ, Gwiazdowicz^ 61— Department ofForest and Environment Protection, August Cieszkowski Agricultural University, ul. Wojska Polskiego 71c, 60-625 Poznan, Poland

Jerzy Bloszyk Department of Animal Taxonomy and Ecology, Adam Mickiewicz University, ul. Szamarzewskiego 91A, 60-569 Poznan, Poland

Tadeusz Mizera Department of Zoology, August Cieszkowski Agricultural University, ul. Wojska Polskiego 71c, 625 Poznan, Poland

PlOTR TRYJANOWSKI Department of Behavioural Ecology, Adam Mickiewicz University, ul. Umultowska 89, 614 Poznan, Poland

Key Words: White-tailed Sea Eagle, Haliaeetus albicilla; quate. Recently, the acarofauna of small passerine nests nest biology, mites', Mesostigmata', Poland. have been studied including detailed studies on Great Reed Warbler {Acrocephalus arundinaceus Reed Warbler ) ,

Although studies on mites living in bird nests were first (A. scirpaceus) Penduline Tit {Remiz pendulinus) and Red- carried out 70 yr ago (Nordberg 1936), knowledge on backed Shrike {Lanius collurio', Masan and Kristofik 1995, al. et al. mite communities in this microhabitat is largely inade- Krikofik et 2001, Tryjanowski 2001). However, information about mites occurring in bird nests is still fragmentary, especially in reference to the acarofauna of

^ Email: [email protected] raptor nests (e.g., Philips 1981, 2000, Philips et al. 1983, . .

March 2005 Short Communications 61

Gwiazdowicz et al. 1999, 2000, Gwiazdowicz and Mizera assemblage were calculated and tested according to Ma- guran (1988). The collected mites were deposited in the 2002 ). Invertebrates Databank (Department of Animal Taxono- In contrast to passerines, many raptor species use their my and Ecology, Adam Mickiewicz University, Poznan, Po- nests for several successive years, which allow communi-

land) . ties of invertebrates to develop. In addition, the relatively long period over which raptor nests are used allows for Results and Discussion temporal changes in acarofauna composition and population dynamics to be observed. Here, we compared the Mite communities recorded in the two nests differed composition of the mite community of the order Meso- from one another both in generic composition and rel- stigmata occurring in two different nests of White-tailed ative abundance of mite species (Table 1). Those differ- Sea Eagle (Haliaeetus albidlla) in Poland over 6 yr (1997- ences were clearly visible in samples from both nests and in subsequent years of the survey. within 2002) . Our work represents the first multi-year observa- the Even one tions of mites using raptor nests. nest, there was wide variation in the apparent abundance of mites and the variety of species that were represented Materials and Methods between samples. Samples collected from the Bytnica Nest material was collected during visits to occupied nest included 11 (2001) to 419 (2002) mite specimens, of two pairs White-tailed nests within the ranges of Sea- and 5 (2000) to 15 (2002) species. The Podanin nests Eagle between 9 May and June 1999-2002. Unlike the 2 contained 11 (2000) to 334 (1998) specimens, and 4 nests of passerines, in which the entire nest is collected (2000) to 10 (1998) species. The total number of species and analyzed after fledging, we collected only ca. 250- of Mesostigmata mites in the Bytnica nest was 29 (696 330 g of the lining material from the nest cup (<0.1% specimens) while the number of species in the Podanin of the entire nest mass). , The samples were collected from both nests. One was nests was only 15 (364 specimes) built in a Scotch pine (Pinus sylvestris) in a forest cluster Out of 35 mite species identified, only 9 (25.7%) were of about 120 yr of age in the Bytnica forest district found in both nests. The Sprensen similarity index (cal- (52°00'N, 15°10'E). The nest was 1.5 m high, 1.8 m in culated from paired samples collected in 1998-2000) was ca. area the diameter and weighed 500 kg. The around very low (similarity = 25%), suggesting that the mite nest comprised moss and boggy ground on the northwest communities in these two nests were distinct from one side and a large pine forest in other directions. Samples another. Uroseius infirmus was the most common species from this nest were collected for 6 yr on the following in the Bytnica nest in 1997 (D = 53%) and 1999 {D = dates: 21 May 1997, 22 May 1998, 6 May 1999, 2 June In 1998 Macrocheles merdarius was most 2000, 28 May 2001, and 29 May 2002. The nest was oc- 34%). common cupied in all years by a pair of White-tailed Sea Eagles, (78%); in 2000 Androlaelaps casalis was most dominant and broods fledged successfully with the exception of the (74%); while in 2001 there were no dominants; and in year 2000, when eggs were laid hut did not hatch. 2002 three species were dominant: Parasitus fimetorum The second nest was located in Podanin forest district (32%), Alliphis siculus (20%), and Macrocheles ancyleus (53°00'N, 16°50'E) and was built in an oak {Quercus^>.) (12%). Alliphis siculus (87%) was dominant in the Podan- within a beech-dominated forest {Fagus sylvatica). This in nest in 1998, Nenteria pandioni (53%) in 1999, and in nest was one of the largest sea eagle nests in western 2000 there were no dominants. Over the 6 yr of survey, Poland (ca. 2.30 m deep and 2.0 m wide, weighing ca. the most commonly identified species in the Bytnica nest 700 kg), and was built from mostly beech boughs with some pine and oak branches (Mizera 1999). The cup- was Parasitus fimetorum, which was also one of the most hning material was comprised of dry grass that probably common in the Podanin nest (examined for 3 yr) . The had been collected from within the forest. Samples from second most numerous species in the Bytnica nest was this nest were collected during 3 yr on the following Alliphis siculus, which appeared “super-dominant” in the dates: 9 11 and 20 May 2000. In all May 1998, May 1999, Podanin nest, comprising 80% of all mites. However, the years, fledglings were produced. third and fourth most numerous species in the Bytnica The mites were extracted in a Tullgren funnel (Karg nest (i.e., Uroseius infirmus and Macrocheles merdarius) were 1993) and preserved in 75% ethanol. Prior to identifi- totally absent from the Podanin nest (Table 1). cation the specimens were kept in lactophenol. Mites also cal- were identified with Axioscop 2 Zeiss microscope Zoocenologic analysis was based on frequency equipped with Nomarsky contrast (Zeiss, Oberkochen, culations. It appeared that Uroseius infirmus (100%) and Germany) Trichouropoda ovalis (83%), classified as euconstants, were The species compositions between the two nests and the most frequent mites in the Bytnica nest. We classified the different years Zoocenologi- among were compared. Alliphis siculus (67%) and Asca nova (67%) as constants. cal analysis of the mite community was based on numer- Nenteria pandioni (100%) was the most frequent in the ical species percentage dominance (dominancy = D) and Podanin nest. We noted that only two species of Uropo- frequency in samples. Dominant species were taken as dina suborder {Nenteria pandioni, Trichouropoda ovalis), those with proportions over 10% of the mite community. The most frequently occurred species were divided into were commonly found in both nests (56—78%) and oc- two groups; 30-50% and >50%. The S0rensen similarity curred regularly in all years. Apart from the two Uropo- index and the Shannon diversity index (TT) of the mite dina species, the lack of a pattern in species composition 62 Short Communications VoL. 39, No. 1

Table 1. List of mite species in two nests of the White-tailed Sea Eagle from Poland. F = female, M = male, D = deutonymph, P = protonymph, and L = larva.

Nest from Bytnica Forest District

Species 1997 1998 1999 2000^^ 2001

Sejina

Sejus togatus Gamasina

Alliphis siculus 7F, 2M 5F, IM IF Androlaelaps casalis 18F, 8M Amblyseius sp. IF IF, IM Ameroseius corbiculus Ameroseius elegans Asca nova 3F IF IF Cornigamasus lunaris Dendrolaelaps latior IIF, IM IF, ID Dendrolaelaps wengrisae IF, IM Dendrolaelaps sp. ID Gamasellodes bicolor IF IF Halolaelaps sp. 5F, 4D IF ID Iphidozercon gibbus Lasioseius sp. Leioseius sp. Macrocheles ancyleus Macrocheles glaber Macrocheles merdarius 55F, 25M Macrocheles tridentinus IF Neojordensia sinuata Paragamasus vagabundus IF IF IF Parasitus coleoptratorum Parasitus fimetorum Pergamasus mediocris 3F, 2M Proctolaelaps pygmaeus Prozercon kochi IF Typhlodromus pyri IF Vulgarogamasus kreaepelini ID IF, IM, 16D Zercon curiosus Zercon triangularis Zercon zelavaiensis IF, IM Uropodina

Nenteria pandioni IF, IM, ID IF, 2D Trichouropoda ovalis 4M IM 3M, 2D, IL 2D Uroobovella marginata ID Uroseius infirmus 24F, 13M, 2M, ID 4F, lOM, 3D, IF IF, ID, IP ID, 2P IP Number of species 10 9 10 5 7 Number of specimens 75 103 53 35 11

No nestlings produced in 2000. March 2005 Short Communications 63

Table 1 . Extended.

Nest from Bytnica Forest District Nest from Podanin Forest District

Total Domi- Total Domi- Speci- NANCY Speci- nancy 2002 mens [%] 1998 1999 2000 mens (%)

IF 1 0.14

43F, 14M, 27D 100 14.37 152F, 87M, 51D IM 291 79.95 13F, 2M 41 5.89 IF, ID 2 0.55

IF 1 0.27 3 0.43 3F 3 0.82 IF 6 0.86

2F, 18D 20 2.87 ID 1 0.27 14 2.01 2 0.29 1 0.14 2M 2 0.55 2 0.29 11 1.58 3F, IM 4 0.57

IF 1 0.27

IM 1 0.14 46F, 4M 50 7.18 35F, IIM, 2D 48 6.90 6F 86 12.36

1 0.14

IF 1 0.27 3 0.43 IF, IM, ID 3 0.82 6F, 2M, 128D 136 19.54 3F, 16D IF, ID 21 5.77 IF 6 0.86

IF 1 0.14

1 0.14

19 2.73 ID 1 0.27 2F 2 0.55

IF 1 0.27 2 0.29

6 0.86 4F, IM, 4D, 8P 6F, 3M, ID IF, IM, 3D 32 8.79 17F, 9M 39 5.60 IM ID 2 0.55 1 0.14 7F, 5M, 13D 90 12.93

15 29 10 6 4 15 419 696 334 19 11 364 64 Short Communications VoL. 39, No. 1

suggests that the occurrence and abundance of mite spe- 2000, Gwiazdowicz 2003) . However, preliminary compar- cies may be influenced by stochastic factors. We suggest isons with White Stork ( Ciconia ciconia) and small passer- that the mite communities in these nests were highly in- ines from nest boxes (Gwiazdowicz 2003, J. Bloszyk un- stable, and that the generic compositions were the result publ. data) suggest differences from these kinds of nests of random factors. Changes in the number of genera ob- For example, in White Stork nests Alliphis siculus (a dom- served over the years were clearly correlated with the inant species in White-tailed Sea Eagle nests), was not changes of mite numbers (r = 0.81; P < 0.01). found. In contrast Androlaelaps casalis was detected as a The Shannon diversity index differed between years in dominant species in nest boxes but was rare and uncom- both nests (Bytnica nest, H = 1.709 ± 0.816; Podanin mon in White-tailed Sea Eagle nests. nest H = 1.082 ± 0.444) and probably was related upon The results presented here are preliminary and further whether or not the nest was successful, because the lowest research is needed, especially to examine potential rela- species diversity (iT = 0.828) was recorded in the nest tionships between mite fluctuations and features of the with no nestlings. The generic diversity recorded in the nest. nest when no nestling was reared differed significantly {t

= 2.42, df = 5, P = 0.05) from that recorded in the same Acaros (Acari: Mesostigmata) Presentes en Dos Nidos nest in successful years. DE HALIAEETUS ALBICILIA Variation in the number of mite species and abun- Resumen.—Se estudiaron los acaros del suborden Mesos- dance during this survey support the hypothesis of high tigmata en dos nidos de Haliaeetus albicilla. Las muestras variability of the Mesostigmata community in the unsta- del primer nido fueron colectadas a lo largo de seis ahos ble microhabitat of White-tailed Sea Eagle nests. Howev- las del segundo a lo largo de tres ahos. Los grupos de er, our results were based on only two nests. Also, we do y acaros de los dos nidos presentaron diferencias marcadas not know whether our removing of samples each year en cuanto a composicion generica abundancia relativa. may have affected the mite community that was present y En el primer nido se registraron 29 especies 696 espe- the following year. y cimenes, mientras que en el segundo solo se encontraron Three species of the Uropodina suborder, Nenteria pan- 15 especies 364 espedmenes. En total, en los dos nidos dioni, Uroseius infirmus, and Trichouropoda orbicularis, y se encontraron 35 especies, de las cuales solo nueve fue- seemed to be typical nidicoles associated with White- ron abundantes en ambos nidos. Las especies dominan- tailed Sea Eagle nests. All three species are phoretically tes en el primer nido fueron Parasitus fimetorum transferred by insects. However, the most consistently-oc- (19.54%), Alliphis siculus (14.37%) Uroseius infirmus curring species in the microhabitat of the eagle nests y (12.93%), en el segundo dominaron Alliphis siculus among Gamasina were Alliphis siculus, Asca nova, Perga- y (79.95%) Nenteria pandioni (8.79%). masus vagabundus, and Parasitus fimetorum. y [Traduccion del equipo editorial] Because eagle nests are reused year after year and mite species can persist from one year to the next, the year to Acknowledgments year variety of mites that might be available to populate A grant by the August Cieszkowski Agricultural Uni- a nest may be masked. The eagle nest mite populations versity of Poznan and Adam Mickiewicz University (Re- did not show regular, seasonal changes, but rather chang- search Project No. 5/L/15/WJ/03) funded this work. es were irregular with no distinct trends. We suggest that Thanks also to M.J. McGrady, J. Phillips, and two anony- eagle nest mite occurrence and abundance depends mous referees who reviewed and improved this manu- mainly on changes in climatic conditions throughout the script. year and the microclimate inside the nest, and is related Literature Cited to nest specific differences (e.g., nest success, nest-lining composition, amount and type of prey remains, and the Gwiazdowicz, DJ- 2003. Mites {Acari, Mesostigmata) ap- amount of excrement) . Importantly, the availability of po- pearing in Poland, in the bird’s nests of Passeriformes, tential prey for the mites depends on the presence of Falconiformes and Strigiformes orders. Pages 562-572 tn decaying flesh (mainly fish and water birds) in the nest, A.T. Miler [Ed.], Ksztaltowanie i ochrona srodowiska and the amount of eagle excrement. Fluctuation in rap- lesnego. Wydawnictwo Akademii Rolniczej, Poznan, torial-mite numbers may also be influenced by the oc- Poland. currence of nematodes, and the eggs and larvae of some AND T. Mizera. 2002. Preliminary research on insects upon which the mites feed. mites {Acari, Gamasina) occurring in the pellets of results on the species structure of mesostigmatic Our birds of prey and owls. Anim. Sci. J. 4:117-125. mites recorded in White-tailed Sea Eagle nests were sim- , AND M. Skorupski. 1999. Mites in Greater , ilar to results on acarofauna found in other raptor nests, Spotted Eagle nests./. Raptor Res. 33:257-260.

including the Spotted Eagle {Aquila clanga) , Lesser Spot- , , AND . 2000. Mites {Acari, Gamasi- ted Eagle {A. pomarina), Osprey (Pandion haliaetus). Red na) from the nests of birds of prey in Poland. Buteo Kite {Milvus milvus), Black Kite {M. migrans), and Com- 11:97-100. mon Buzzard {Buteo buteo) (Gwiazdowicz et al. 1999, Karg, W. 1993. Acari (Acarina), Milben Parasitiformes ,

March 2005 Short Communications 65

(Anactinochaeta) , Cohors Gamasina Leach. Fischer gen liber die Vogelnidicolen. Acta Zool Fenn. 21:1- Verlag, Jena, Germany. 168.

KristofikJ., P. Masan, and Z. Sustek. 2001. Mites (Acan), Philips, J.R. 1981. Mites {Acarina) from nest of Norwe- beetles (Coleoptera) and fleas (Siphonaptera) in the gian birds of prey. Fauna Nor. Ser. B. 28:44—47.

nests of Great Reed Warbler (Acrocephalus arundinac- . 2000. A review and checklist of the parasitic mites {Acarina) of the Falconiformes and Strigiformes. Raptor beus) and Reed Warbler (A. scirpaceus) . Biologia {Bra- J Res. 34:210-231. tislava) 56:525—536.

, M. Root, and P. Desimone. 1983. Arthropods Maguran, A.E. 1988. Ecological diversity and its measure- from a Saw-whet Owl {Aegolius acadicus) nesting ment. Groom Helm, London, U.K. m Connecticut. Entomol. News. 94:60—64. Masan, P. and J. Kristofik. 1995. Mesostigmatid mites (Ac- TRYfANOWSKI, R, E. Baraniak, R. Bajaczyk, DJ. Gwiazdow- arina: Mesostigmata) in the nests of Penduline Tit {Re- icz, S. Konwerski, Z. Olszanowski, and P. Szymkowiak. miz pendulinus) . Biologia {Bratislava) 50:481—485. 2001. Arthropods in nests of the Red-backed Shrike Mizera, T. 1999. Bielik. Wydawnictwo Lubuskiego Klubu collurio) {Lanius in Poland. Belg. J. Zool. 131:69—74. Przyrodnikow, Swiebodzin, Poland. Nordberg, S. 1936. Biologisch-Okologische untersuchun- Received 16 February 2004; accepted 25 October 2004

Vertebrate Prey of the Barn Owl ( Tyto alba) in Subtropical Wetlands oe Northeastern Argentina and Eastern Paraguay

Ulyses F.J. Pardinas and Pablo Teta^ Centro Nacional Patagonico, Casilla de Correo 128, 9120 Puerto Madryn, Chubut, Argentina

Sofia Heinonen Fortabat Administracion de Parques Nacionales, Delegacion Tecnica Regional Nordeste. Avenida Victoria Aguirre 66, 3370, Iguazu, Misiones, Argentina

Key Words: Barn Owl; Tyto alba; Iberd-Neembucu Wet- mosaic of marshes, “embalsados" (massive carpet of float-

lands; diet, prey biomass; Argentina; Paraguay. ing vegetation, mostly composed of accumulated, dead, and decomposing plant material). These wetlands are in- termixed with extensive palms of Copernicia alba and gal- In South America, the diet of the Barn Owl ( Tyto alba) lery forest, and have remained mostly unmodified by hu- has been studied primarily in temperate and arid regions man activities (Carnevali 1994). The climate is humid of Argentina and Chile (Jaksic 1996, Pardinas and Cir- subtropical (according to Koppen’s [1931] classification ignoli 2002). In the vast tropical and subtropical-humid scheme), with a mean annual temperature of 23-C and areas this owl is poorly known (e.g., Motta-Junior 1996, mean annual precipitation of nearly 1350 mm (Carnevali Bellocq 2000, Vargas et al. 2002). Here, we describe the 1994). vertebrate prey consumed by Barn Owls in the subtropical wetlands of the Ibera-Neembucu system (Argentina Methods and Paraguay). The owl-pellet samples {N = 14) were collected during the breeding seasons of 2001-02 and 2002—03 (Septem- Study Area ber-December) from human buildings at 1 1 localities m The Esteros del Ibera (Corrientes Province, Argentina) the Ibera-Neembucu wetlands (Fig. lA). Because of the

IS a Ramsar site of 13 000 km^, making it one of the larg- humid environment, pellets rapidly disintegrated (<1 est wetlands in South America. The Esteros del Neem- mo). Therefore, the precise number of pellets included bucu (Neembucu Department, Paraguay), with ca. 4000 was undetermined. We also included two samples of pel- km^, cover an extensive region on the left bank of Para- let debris (localities of Ensenadita and Desaguadero) guay River. Both wetlands (Fig. lA) display a complex from the west border of Ibera, at a site previously studied by Massoia et al. (1988, 1990). Only vertebrates were considered in this study; inver- 1 Email: [email protected] tebrates (mainly insects) were also present in some sam- 66 Short Communications VoL. 39, No. 1

Table 1. Vertebrate prey items found in pellets of the Barn Owl from Ibera-Neembucu wetlands (Argentina and

Paraguay). Numbers in parentheses refer to Figure 1. Percent biomass (%B) are given in grams (g) for samples with N> 50.

Ea. San Ensena- Desagua- El Som- El Pon- Ea. Cerro Ignacio

PlIAR (1) DITA (2) DERO (3) brero (4) ton (5) Pyta (6) (V) Mass N %B N %B N %B N %B N %B N %B N %B

Rodents

Akodon azarae 28 15 4.8 — — 30 1.9 14 0.7 6 0.4 6 1.2 — — Akodon montensis 39 — — — — — — 5 0.4 — — — — — —

Calomys cf. C. callosus 31 — — 1 1.1 41 1.8 24 1.3 34 2.7 2 0.5 — — Cavia aperea 525 — — — — 13 9.6 1 0.9 2 2.7 — — 3 8.2 Holochilus sp. 150 44 75.9 6 31.1 270 56.9 313 84.3 197 75.8 68 74.3 113 88.0 Necromys temchuki 47 — — 8 13.0 69 4.6 32 2.7 49 5.9 — — — —

Oligoryzomys cf. O. flavescens 22 — — — — — — 3 0.1 8 0.5 — — — —

Oligoryzomys cf. 0. flavescens 17 20 3.9 6 3.5 101 2.4 28 0.9 41 1.8 85 10.5 6 0.5 Oxymycterus rufus 76 — — 3 7.9 33 3.5 20 2.7 20 3.9 3 1.7 1 0.4 Rattus sp. 160 3 5.5 — — 3 0.7 — — — — — — — — Scapteromys aquaticus 112 3 3.9 4 15.5 64 10.1 25 5.0 18 5.2 3 2.5 3 1.7 Opossums

Gracilinanus sp. 15 — — — — 22 0.5 7 0.2 8 0.3 — — — — Lutreolina cmssicaudata 445 — — — — 12 7.5 Marmosini, unidentified 18 7 1.4 5 3.1 — — — — — — 72 9.4 13 1.2

Bats

Eumops patagonicus 13 4 0.6 46 20.6 — — 2 0.1 2 0.1 — — — — Eumops perotis 64 — — — — 1 0.1 Molossus ater 30 — — 1 1.1 2 0.1 2 0.1 1 0.1 — — — —

Molossus molossus 19 — — — — 4 0.1 — — 1 0.1 — — — —

Amphibians, unidentified 8 — — — — 1 0.1 10 0.1 — — — — — — Birds, unidentified 31 11 3.9 3 3.2 24 1.0 9 0.5 — — — — — —

Total prey items 107 83 690 495 387 239 139 FNBi 4.14 2.98 4.91 2.23 3.33 3.34 1.49 FNBsi 0.45 0.22 0.26 0.10 0.19 0.39 0.10 MGWP2 81.1 34.9 103 112 97.1 57.5 138

' FNB = food-niche breadth and FNBs = standardized food-niche breadth; see methods. ^MGWP = geometric mean of weight of prey.

pies, but their proportion was negligible. Osteological re- mean mass of 150 g for this species in biomass estima- mains were identified by comparison with the reference tions. The trophic niche breadth was measured accord- mammal collection of the Centro Nacional Patagonico, ing to the Levins index, food-niche breadth (FNB = 1/ Puerto Madryn, Argentina. We followed the taxonomy in 2 p,^, where pi = proportion of each prey), and the Galliari et al. (1996). For each prey type, we quantified standardized Levins index (FNBs = [FNB — minimum] / the minimum number of individuals (MNI; determined [FNB maximum — FNB minimum], where FNB mini- by skull bones) and the percent biomass contribution to mum = 1 and FNB maximum = maximum number of the diet (percent biomass = [100 NJ/2 pi N^, where prey categories [species for mammals, classes for am-

= mean prey ^ mass and A( ~ number of individuals of phibians and birds]; Marti 1987). the prey i). The mean prey mass were taken from literature (Redford and Eisenberg 1992) and from specimens Results and Discussion trapped in Corrientes Province (unpubl. data). Mass of We identified 2262 prey items, mostly native-sigmodon- the marsh rat {Holochilus sp.) counted in pellets was estimated from comparisons to skeletons of this rodent of tine rodents (>90%). The more frequently preyed-upon known mass collected near the study area. Large adult species were the oryzomines Holochilus sp. and Oligoryzo- Holochilus may exceed 200 g in body mass; we used a mys cf. O. flavescens. Other muroids recorded were Akodon March 2005 Short Communications 67

Table 1 . Extended.

Ea. El Ea. P.N. Ea. San Estribo Yaguarete Mburu- Pto. Maria

Paso Lucero (8) Antonio (9) (10) Cora (11) Ea. IberA (12) cuya (13) Cristina (14) N %B N %B N N N %B N N %B — — — — — — — —38 14.9— — — — — — — — 183— 26.4— 23 10.0 — — — — — — — — — — — 7 16 — — — — — — — —28 58.7— 107— 72— —11 —7 —27 61.3— —3 —72 55.7—

— — — — — — 2 0.7 1 3 0.3 —61 14.5— —43 —3.3 —3 —22 —80 20.6— 8 98 8.6 — — — 3 2 0.8

7 3.5 8 13.6 1 11 6.4

— — 7 0.5 — 1 — — 1 — — Q c 4.0

1 0.3 3 14 3.8 12 1.1

— — — — — 1 — — — — — 2

— — — — — — — 4 0.2 4 1.7 3 0.5

155 173 14 36 131 17 388 3.70 2.23 — — 2.02 — 3.10 0.54 0.25 — — 0.34 — 0.26 46.2 128 — — 45.9 — 49.9

azarae, Calomys cf. C. callosus, Necromys temchuki, Oxymycte- (GMWP) was 34.9-138.6 g. Six samples showed GMWP rus rufus, and Scapteromys aquaticus. The Barn Owl also values >80 g (110.2 ± 21.1 g; x ± SD). For South Amer- consumed variable numbers of marmosine marsupials, ican temperate latitudes, Marti et al. (1993) reported a molossid bats, birds, and amphibians (Table 1 ) . Although GMWP of 45.1 g. Clearly, the greater values obtained for the representation of the latter groups in pellets was lim- the Ibera-Neembucu system were related to a greater ited, the bat Eumops patagonicus was the most common consumption of prey with mass >100 g. The high pre- prey in the Ensenadita sample. On the other hand, the dation on Holochilus sp. (150 g) was unusual, because marmosine marsupials were the second most frequently Barn Owls typically capture smaller prey (Taylor 1994) consumed prey in the samples from the estancias Cerro- Similar results were reported by Vargas et al. (2002) in a Pyta and San Ignacio. tropical flooded savanna from northern Bolivia and by

In terms of biomass, Holochilus sp. was the most im- Massoia et al. (1997, 1999) for owls inhabiting the right portant prey in the diet (31.1-87.9%), followed hy Akodon bank of the Rio Parana in the Argentinean provinces of azarae, Cavia aperea, and Scapteromys aquaticus, with esti- Chaco and Formosa. Most of the Holochilus sp. individuals mates generally <15% (Table 1). The prey mass range recovered in Ibera-Neembucu pellets were, on the basis was between 8 g (amphibians) and 445 g {Lutreolina cras- on tooth wear, full adult or old-adult specimens. This im- stcaudata). The geometric mean of weight of prey plied that the actual mass of these individuals was close ,

68 Short Communications VoL. 39, No. 1

Neembucu system supports the conclusion that Barn Owls specialized on a small number of prey types. The mean number of mammalian genera in owl pellets was 7.81 ± 2.99 {x ± SD), with a range between 4—13. In

the Corrientes Province, the small mammal diversity is

higher toward the confluence of the Parana-Paraguay rivers. The recorded number of rodent species near the

central part of Ibera system is clearly smaller, which is probably related to the homogeneity of the environment In fact, the participation in the assemblages of species such as Akodon spp., C. callosus, N. temchuki, and O. rufus increases progressively toward the periphery of the wetlands system. Trapping conducted in Ibera area showed that these rodents preferred grasslands in upland zones, while the extensive marsh areas were dominated by Hol-

ochilus spp. and Oligoryzomys spp. (Fabri et al. 2003). These general trends in rodent species richness were reflected in the Barn Owl diet (Fig. IB). The species richness of small rodents in owl pellets for central localities from Ibera-Neembucu system ranged from 2-6 {N = 9 samples; x = 4.6 species). In contrast, for western marginal localities this value reached 10 {N = 4 samples, x = 8.5 species).

These contrasts, comparing central and peripheral localities, were also evident in differential predation on

other groups of mammals, such as bats (Table 1). Al- though bats are not a common prey of the Barn Owl

(Vargas et al. 2002), their frequency increased toward the northwestern study area, becoming the most abundant item in one locality (Ensenadita). Einally, in sharp contrast to what we would have predicted for a flooded and subtropical area, amphibian consumption was almost zero, despite the high diversity of this group in the Ibera Figure lA, Map of the study area, northeastern Argen- system (Alvarez et al. 2002) . Perhaps, most of the anurans tina and southeastern Paraguay, showing the localities of the Neembucu-Ibera system were “avoided” by owls discussed in the text in the Neembucu-Ibera wetlands. because of their cryptic habits and small body mass (<8 IB. Specific richness (rodents) found in pellets of Barn

g) . Antipredator mechanisms in toads and frogs also in- Owls from Ibera-Neembucu wetlands. Only localities with clude defensive postures and toxic or noxious skin secre- more than 50 individual prey items identified were in- tions that may deter predation hy Barn Owls. On the cluded. Locality names for numbers are provided in Ta- other hand, the high consumption of Holochilus in these ble 1. large subtropical wetlands could be related to the fully-

nocturnal habits of this amphibious rodent, its high de-

gree of exposure during its feeding activities in open ar- to 200 g (Massoia 1976). On the other hand, in samples eas, and the enormous densities of this marsh rat m mainly composed of smaller species (e.g., Ahodon azarae, subtropical wetlands (Massoia 1976). Eumops patagonicus, Oligoryzomys spp.) the GMWP varied between 34.9-57.4 g, with a mean value (46.9 ± 8.2 g), Vertebrados Presa de Tyto alba en Humedales Sub- similar to the value previously reported by Marti et al. TROPICALES DEL NORDESTE DE ARGENTINA Y ESTE DE PAR- (1993). AGUAY The FNB was 1.49-4.14 (2.79 ± 1.29; x ± SD), and the FNBs was 0.10—0.45 (0.28 ± 0.14; x ± SD). These results Resumen.—Se estudio la dieta de Tyto alba en los hume- are similar to those previously estimated by Bellocq dales del complejo de esteros Ibera-Neembucu, ubicados (2000) for the Ensenadita and Desaguadero samples en el nordeste de Argentina y este de Paraguay. Se iden- (FNBs = 0.25 ± 0.04). In South America, Marti et al. tificaron 2262 presas, con una neta predominancia de (1993) reported a FNB of 4.28 (FNBs = 0.48) in tem- roedores sigmodontinos nativos (>90%). Holochilus sp. y perate latitudes, and 4.61 (FNBs = 0.38) in tropical lati- Oligoryzomys cf. O. flavescens fueron las especies mejor re- tudes. The lower values of the Levins index for the Ibera- presentadas. La media geometrica del peso de las presas .

March 2005 Short Communications 69

consumidas asumio valores entre 34.9-138.6 g y la am- Koppen, W. 1931. Grundiss der Klimakunde. Walter de plitud de nicho trofico fluctuo entre 1. 5-4.1. Es desta- Gruyter Co., Berlin and Leipzig, Germany. cable el importante consumo de presas con un peso Marti, C.D. 1987. Raptor food habits studies. Pages 67-

>100 g, que se refleja en una media geometrica del peso 80 in B. Giron Pendleton, B.A. Millsap, K.W. Cline, de las presas >80 g. Igualmente destacables son los bajos and D.M. Bird [Eds.], Raptor management tech- valores de riqueza de roedores que se observan en aque- niques manual. National Wildlife Federation, Wash-

llas localidades centrales al sistema de humedales (entre ington, DC U.S.A.

2—6 especies), en contraste con los observados en loca- , E. Korpimaki, and F. Jaksic. 1993. Trophic ecol- lidades perifericas del oeste (entre 6-11). En estos am- ogy of raptor communities: a three-continent com-

bientes inundables subtropicales, la dieta de T. alba se parison and synthesis. Curr. Ornithol. 10:47-137. focaliza basicamente en el consumo de Holochilus sp., un Massoia, E. 1976. Mammalia. Pages 1-128 mR. Ringuelet roedor anfibio netamente nocturno que alcanza grandes [Ed.], Fauna de agua dulce de la Republica Argenti- densidades poblacionales. na. Fundacion Editorial Ciencia y Cultura, Buenos Ai- [Traduccion de los autores] res, Argentina.

, J.C. Chebez, and S. Heinonen Fortabat. 1988. Acknowledgments Presas de Tyto alba tuidara en Ensenadita, departamento San Cosme, provincia de Corrientes. Biol, We thank the many individuals that freely provided dent. Natur. 12:8-14. samples, data, or field and laboratory assistance for this

. , , 1990. study: A. Andrade, J.R. Contreras, Y Davies, S. Fabri, L.M. AND Mamiferos depreda- Fuschetto, M. Merino, and A. Soria. We appreciated the dos por Tyto alba tuidara en Desaguadero, departa- improvements in English usage made by Stacy Small mento capital, provincia de Corrientes. Biol. dent. Na- through the Association of Field Ornithologists’ program tur. N^ 18:14-17. of editorial assistance. Field work supported Ibera was by , S. Heinonen Fortabat, and A.J. Dieguez. 1997 Project (Universidad Nacional del Nordeste, Corrientes). Analisis de componentes mastozoologicos y ornitolo- partially the This work was funded by Consejo Nacional gicos en regurgitados de Tyto alba de Estancia Guay- de Investigaciones Cientificas Tecnicas (CONICET) y colec, departamento. Pilcomayo, provincia de For- mosa, Republica Argentina. Biol. dent. Natur. N- 32 Literature Cited 12-16.

Alvarez, B.B., R.H Aguirre, J.A. Cespedes, A.B. Hernan- , H. Pastore, and S. Heinonen Fortabat. 1999 Analisis de regurgitados de Tyto alba escuela pro- do, AND M.E. Tedesco. 2002. Atlas de anfibios y rep- en vincial N-17 Sabiaur” departamento Bermejo, tiles de las provincias de Corrientes, Chaco y Formo- “J. sa, Argentina: anuros, cecilidos, saurios, anfisbenidos provincia de Chaco. Biol. dent. Natur. N- 36:2-4. Motta-Junior, C.J. 1996. Ecologia alimentar de corujas y serpientes. Univ. Nacional del Nordeste, Corrientes, Argentina. (Aves, Strigiformes) na regiao central do estado de Sao Paulo: biomassa, sazonalidade e seletividade de Bellocq, M.I. 2000. A review of the trophic ecology of suas presas. Tese de Doutorado, Univ. Federal de Sao the Barn Owl in jArgentina. y. Raptor Res. 34:108-119. Carlos, Sao Carlos, Brazil. Carnevali, R. 1994. Fitogreografia de la Provincia de Pardinas, U.F.J. and S. Cirignoli. 2002. Bibliografia com- Corrientes. Institute Nacional de Tecnologia Agro- entada sobre los analisis de egagropilas de aves rapa- pecuaria, Edicion de la Gobernacion de la provincia ces en Argentina. Ornitol. Neotrop. 13:31-59. de Corrientes, Corrientes, Argentina. Redeord, K.H. andJ.F. Eisenberg. 1992. Mammals of the Fabri, S., S. Heinonen Fortabat, A. Soria, and U.F.J. neotropics. Vol. 2. The southern cone: Chile, Argen- Pardinas. 2003. Los mamiferos de la Reserva Provin- tina, Uruguay, Paraguay. Univ. Chicago Press, Chica- cial Ibera, provincia de Corrientes, Argentina. Pages go, IL U.S.A. 305-342 in B.B. Alvarez [Ed.], Fauna del Ibera. Edi- Taylor, I. 1994. Barn Owls, predator-prey relationships, torial Universitaria de la Universidad Nacional del and conservation. Cambridge Univ. Press, Cambridge, Nordeste, Corrientes, Argentina. U.K. Galliari, C.A., U.F.J. Pardinas, and F. Goin. 1996. Lista Vargas J., C.A. Landaeta, and J.A. Simonetti. 2002. Bats comentada de los mamiferos argentinos. Mastozool. as prey of Barn Owls ( Tyto alba) in a tropical savannah Neotrop. 3:39—62. in Bolivia./. Raptor Res. 36:146-148. Jaksic, F. 1996. Ecologia de los vertebrados de Chile. Ed- iciones de la Universidad Catolica de Chile, Santiago, Received 20 November 2003; accepted 26 November Chile. 2004 ,

Absence oe the Eurasian Griffon {Gyps fulvus) in Northern Morocco

Jose Rafael Garrido

Departamento de Zoologia, C.E.S. Marcelo Spmola-University of Wales, Plaza del Arzobispo 1, 41806 Umbrete, Spain

Alvaro Camina^ Apartado de Correos 339, 28220 Majadahonda, Madrid, Spain

Mariangela Guinda and Maria Egea

Departamento de Zoologia, C.E.S. Marcelo Spinola-University of Wales, Plaza del Arzobispo 1, 41806 Umbrete, Spain

Nourdine Mouati Departement de Biologie, Faculte des Sciences, Universite Abdelmalek Essaddi BP.2121 Tetouan, Morocco

Alfonso Godino and J.L. Paz de la Rocha Calle Cristo del Gallo 2, 23400 Ubeda, Jaen, Spain

Keywords: Eurasian Gaiffow, Gyps fulvus; breeding range, through this country before reaching wintering grounds Morocco; wintering. in the southern Sahara.

Study Area and Methods The Eurasian Griffon {Gyps fulvus) is a Palearctic species distributed from North Africa, south and southeast- This study was done in northern Morocco, from the ern Europe to the Middle East into southwestern and North Atlantic Coast (60 km north of Kenitra) to the eastern Sahara Desert (Plateau du Rekkam) through the central Asia (Cramp and Simmons, 1980, del Hoyo et al. Rif (Ouazzane-Chefchauoen-Ketama-Midar to Oujda) 1994). In the last three decades the Spanish population and the Middle Atlas Mountains (from Meknes to Taza) has greatly increased (SEO BirdLife 1981, Arroyo et al. and from Guercif into An-Benimathar south as far as 1990, del Moral and Marti 2001). Migration of the spe- Bouarfa, near Figuig. The southernmost surveyed point cies into Africa through the Strait of Gibraltar to Moroc- in central Morocco was Meknes. The study area is similar co and countries south of Sahara has been studied for a to the Spanish side of the Strait of Gibraltar from the long time (Elosegui and Elosegui 1977, Bernis 1983, ecological and geological points of view (Valdes 1991) Many large limestone mountains provide cliffs with suit- Aonso 1984, Griesinger 1998). However, there is limited able caves and surfaces for Eurasian Griffons to breed recent information on the status of the species in Mo- (del Hoyo et al. 1994). On the Spanish side, one of the rocco. The information available only describes breeding largest breeding subpopulations in Spain was found (del colonies documented in the past (Soto 1986, Bergier Junco and Barcell 1997, del Moral and Marti 2001). How- 1987). Mundy et al. (1992) referred to some colonies in ever, on the Moroccan side there were breeding colonies the Rif Mountains close to Tangier and additional ones only in the past (Soto 1986, Bergier 1987, Thevenot et from Figuig in the east to Goulimine on the west of the al. 2003). Some authors believe that griffons may still Anti-Atlas, with no breeding places in the Sahara Moun- breed there in Morocco, but the whole area has been heavily populated and hence changed dramatically (Had- tains. According to Haddane (1996) and others, the dis- dane 1996). tribution of griffons in Morocco has been reduced dras- Roadside counts covering ca. 2800 km were done dur- tically by human activities, and generally recent ing one entire month (1-28 February 2002). On those information (Mundy 2000, Thevenot et al. was not 2003) dates, adult Eurasian Griffons are breeding (laying or in- supported with fieldwork. The extent of the population cubating) and non-adult migrating birds should still be decline of griffons and their winter distribution in Mo- on their wintering grounds (del Hoyo et al. 1994, pers rocco remain unknown. Our aim here is to: (1) survey obs.). Our survey was done using a vehicle, at a speed of for the Eurasian Griffon breeding colonies in northern ca. 40-50 km/h with stops when colonies were located We looked for cliffs with raptor excrement (white wash), Morocco and (2) analyze the recoveries of ringed birds as well as perched and flying vultures (Fuller and Mosher from Spain to identify potential wintering grounds. The 1981, Donazar et al. 1993). We searched for griffons at status of the species in Morocco is relevant to its conser- any suitable cliff within view of our road surveys and at vation. Al migrating western European vultures cross potential feeding sites such as rubbish dumps or places where livestock carcasses were dumped. During surveys, we used 10 X 40 binoculars and a 20-45 X scope. We ^ Email address: [email protected] assumed that our detection probability of the birds from

70 . ,

March 2005 Short Communications 71

the road survey routes was very high. Detection of griffons is highly likely due to their large size and their flock- ing behavior in diffuse groups (Donazar 1993). We also included supplementary information collected at other sites during short-term visits throughout the typical breeding season (January-June) Additionally, we made 55 inquiries to local people who were familiar with the species, managers of the Moroccan Environment Agency, and foreign ornithologists with a good knowledge of birds in Morocco. Photographs of both perched and flying griffons were shown to local individuals to help determine if they had seen these vultures. We also asked if these local residents knew of breeding colonies, if they had seen griffons on a year- round basis, and if so, when, where, and how many birds they had seen. Also, we inquired about the attitude of people toward griffons and other raptors.

Finally, to complete our assessment of Eurasian Griffon Figure 1. Map of Morocco showing the recoveries of status in Morocco we examined all the recoveries of birds Griffon Vultures ringed in Spain (numbers as in Table ringed in Spain from 1965-2002. The following databases 1) and locations of reported observations of griffons were reviewed: Centro de Migracion de Aves (SEO/ 1^1 The study area in northern Morocco is outlined.

BirdLife) , Direccion General de Conservacion de la Na- turaleza (DGCN) from the Spanish Ministry of Environ- ment, and Museo de Ciencias Aranzadi from San the study area, plus in the eastern desert anoth- Sebastian. one and er in the Atlas Mountains (Fig. 1). All were made on the Results Mediterranean side of Morocco and in the Rif Moun- tains. People interviewed said that groups of vultures did see griffons during the roadside census We not any were never seen for long periods. The mean group size breeding at previously-reported colonies. or any We was 6.5 ± 6.2 (SD) griffons (range = 1—73). Further- searched for colonies, but found none in the Jebel Mous- more, no information was reported on recent breeding sa in Tangier region, the Jebel Bouhachen Nature Re- colonies. Only one record involved griffons feeding on a serve, and Jebel Haouz (Soto 1986). We surveyed Bab carcass near Tangier. Observations were sparsely distrib- Taza, visiting Tissouka, Lahkrtia, Jebel el-Kelaa, Jebel Ab- uted throughout the year: five in winter (December-Feb- doune, and Talambote, as well as the Oued Laou can- ruary), seven in spring (March-May), four in summer yons. We also passed through Talaseemtane National (June-August), and three in autumn (September-No- Park and the Ketama (Jebel Tidiquim) Mountains sur- vember). Observers provided six records (20.8%) for rounding de Targuist and Al-Hoceima National Park, which they could not recall the season. Everyone inter- close to the coast. In addition, we visited the Middle Atlas viewed pointed out that griffons, as well as other raptors, at Tazzeka National Park. Other colonies mentioned by were shot and even consumed by man. Moreover, five Soto (1986) and visited with negative results were Bou older residents remembered the species from their Bgar (Gorges de la Moulouya), nearby Oujda city. Fur- youth, when wild ungulates and big felids, such as lions thermore, two recorded colonies in Massif des Beni Snas- {Panthera led) or leopards {Panthera pardus) inhabited the sen had no griffons. Our lack of detections suggests that area. These individuals reported that griffons were pres- there were neither breeding nor wandering birds in the ent in the 1960s and 1970s. Finally, one observer report- study area. During our roadside counts we easily detected ed six griffons in the Middle Atlas Mountains (near several cliff-nesting raptors such as Bonelli's Eagles {Hi- Azrou) , although he was unable to recall the date and if eraaetus fasdatus), Peregrine Falcons {Falco peregrinus), they were migrant or resident. Bedouin shepherds indi- and Golden Eagles {Aquila chrysaetos), all more difficult cated that every winter a small griffon population re- to detect than Eurasian Griffons. Therefore, we believe mains in the desert located in the Eastern Atlas Moun- that we did not overlook the latter species. Two rubbish tains, where there is a winter food supply from sheep dumps were visited, one south of Tangier and another carcasses. close to Chefchaouen to the east. None of these seemed We found only nine recoveries of Spanish ringed grif- to support griffons, although there were large numbers fons in different locations of Morocco (Fig. 1 and Table of White Storks ( Ciconia dconia) . Our previous visits to 1). Most of them (except recoveries 8 and 9) were ringed Morocco had revealed no griffons in the L'Oum or Rbia as nestlings, but all were probably ringed as juvenile and El Menzel colonies in 1986 and 1994, respectively. birds. Where information was available, most of the Of 55 questionnaires, only 50 were judged to provide deaths were attributed to malnutrition (Table 1). Three valid information. Based on their reports, 26 respondents had died recently, two were sighted alive, and a sixth grif- observed Eurasian Griffons in the last decade, 24 within fon was maintained in captivity. It is noteworthy that all 72 Short Communications VoL. 39, No. 1

Table 1. Recoveries of ringed Eurasian Griffons in Morocco. Dates (ca. dates are in parentheses), coordinates of ringing and recovery are also shown.

Recov- ery Coordi- Province Circumstances Coordi- Num- Age of Date of nates of of OF Date of nates OF Location of ber Ringing Ringing Ringing Ringing Recovery Recovery Recovery Recovery

1 Nestling 25 Jun 67 42.55N Navarra Captured 02 Nov 70 33.47N Souk KLhemis 01.51W 06.02W Ait Yadine 2 Nestling 19 May 7l 42.38N Huesca na 01 Dec 72 33.16N Timandite 00.49W 05.05W 3 Nestling 12 May 79 40.56N Teruel Corpse alone 02 Oct 80 30.29N Taroudant 00.15W found 08.52W 4 Nestling 29 May 84 36.35N Cadiz 29 Nov 84 33.50N Khemisset 05.50W na 06.03W 5 Nestling 11 May 85 41.21N Segovia 06 Jun 86 33.15N Jorf Lasfar 03.50W Malnutrition 08.40W 6 Nestling 10 May 86 41.29N Soria Predated 06 Jul 87 30.30N Toulgharb 09.40W 09.40W 7 Nestling 18 May 96 42.50N Alava na 24 Feb 98 35.53N Ceuta 03.06W 05.19W 8 na 27 Nov 98 37.00N Huelva na 07 Jan 99 32.16N Rich 06.30W 04.30W 9 Fledgling 10 Sep 99 41.34N Burgos Malnutrition 19 Nov 99 34.57N Midar 03.41W 03.33W

nine griffons were ringed in different Spanish provinces. 2001 (R Bergier pers. comm.). To date, the migration Finally, three were ringed in the 1960s or 1970s, four in period and pattern of griffons has not been analyzed in the 1980s, and four in the 1990s, with no increases in detail (Bernis 1983, Franchimont and Moumni 1996, recoveries despite the increases of both the Spanish pop- Griesinger 1998). Migration phenology in the Strait of ulation and the number of griffons ringed (del Moral Gibraltar area extends even later than October, with large and Marti 2001, Gomez-Manzaneque et al. 2002). numbers still passing in November (SEO/BirdLife 2001). Ring recoveries of griffons were scarce and were not Discussion adequate to draw any conclusions. Recent studies with Our survey revealed a complete lack of breeding or Egyptian Vultures {Neophron percnopterus) tracked with sat- wintering Eurasian Griffons in northern Morocco. This ellite transmitters (Benitez et al. 2003, M. de la Riva pers. could reflect the alarming decline of the species reported comm.) showed broad-band migration over Morocco and by Soto (1986) and Thevenot et al. (2003). According to that the birds followed a straight flight path southwards these authors and this current study, the Eurasian Griffon over the country and the Sahara Desert. Limited data for could be extirpated as a breeding species in this region griffons seem to show a similar migration pattern, al- and probably in all of Morocco. Reasons for this decline though it has been suggested that these vultures follow would be lack of food and direct human persecution by specific routes as they do in Spain (Garrido et al. 2001). means of poaching and poisoning (Soto 1986, Haddane Recoveries of griffons on the Atlantic side could suggest

1996, Thevenot et al. 2003). The same reasons could ex- a second coastal route or vagrant birds. Migration along plain why there are no vagrant griffons in the area, de- this route would likely take griffons to sub-Saharan win- spite that the physical habitat appears suitable. Results of tering quarters in Mauritania, Senegal, and Mali (del inquiries indicated that only migrating griffons from Eu- Hoyo et al. 1994, Layna 1999). A small griffon population rope passed over northern Morocco, and that no locally- could remain in the northern Sahara, if food is available. breeding birds were present. Increasing numbers of grif- In addition to Spanish recoveries, there is another from fons have been recorded crossing into Africa in recent a juvenile griffon ringed in the Pyrenees of France as a years with 1633, 2649, and 4816 birds in 1998, 1999, and nestling in early June 1993 and recovered near Meknes 2000, respectively (SEO/BirdLife 2001). Furthermore, within the same year (5 October; Arthur and Peyrusque up to 1524 were recorded at Koudia el Baida (20 km 2000) that supports the idea of a central broad-band mi- north to Tetouan and 30 km east from Tangier), with gration of griffons. The percentage of ring recoveries in 1426 birds counted on 23 October during a survey in Morocco (2.7%) is lower than that in the Iberian Pen- March 2005 Short Communications 73 insula (5.1%), from 4062 griffons ringed in Spain (G6- vice scientifique N- 99/08/GR, Parc National des Pyr- mez-Manzaneque et al. 2002). Probabilities of reporting enees, Ossau, France. a ringed bird could be biased relatively high in heavily Benitez, J.R., J.A. Sanchez Zapata, J.A. Donazar, populated areas, giving a misleading impression of the M. de la Riva, F. Hernandez, and M. Barcell. 2003. migration route. Nevertheless, the final destination of Andalucia se queda sin Alimoches. Quercus 206:15-19. griffons should be determined by future studies using Bergier, P. 1987. Les rapaces diurnes du Maroc. Status, satellite transmitters (Camina, 2004). repartition et ecologie. Centre d'Etudes sur les Eco- From the conservation point of view, our study indi- systemes de Provence, Aix en Provence, France. cates that the Eurasian Griffon is seriously endangered, Bernis, F. 1983. Migration of the common griffon vulture if not extinct as a breeding species in Morocco. The de- in the western Palearctic. Pages 185-196 in S.R. Wil- cline in the griffon population was probably due to a lack bur and J.A. Jackson [Eds.], Vulture biology and man- of available food and human persecution. For this rea- agement. Univ. California Press, Berkeley, CA U.S.A son, we suggest that it is urgent to examine the status of Camina, A. 2004. Griffon vulture Gyps fulvus monitoring the griffons in Morocco and other African countries in Spain: current research and conservation projects. south to the Sahara to provide information necessary to Pages 45-66 in R.D. Chancellor and B.-U. Meyburg implement conservation measures. [Eds.], Raptors worldwide. World Working Group on Birds of Prey and Owls and BirdLife Hungary, Buda- Ausencia de Gypsfulvus del Norte de Marruecos pest, Hungary. Cramp, S. and K.E,L, Simmons (Eds.). 1980. The birds of Resumen.—Mediante transectos por carretera en el norte the western Palearctic. Vol. 2. Oxford Univ. Press, Ox- de Marruecos (2800 km) y visitas a antiguas colonias de ford, U.K. cria, se han buscado evidencias de cria o invernada del DEL Hoyo, J., a. Elliott, and J. Sargatal. 1994. Hand- buitre Gyps fulvus. Ademas, se han realizado 55 encuestas book of the birds of the world. Vol. 2. Lynx Edicions, a habitantes de Marruecos sobre el estatus de la especie. Barcelona, Spain. No se ha encontrado ningun buitre criando a pesar del DEL JUNCO, O. AND M. Barcell. 1997. El buitre leonado aparente habitat disponible. Los habitantes de la zona ( Gypsfulvus) en Cadiz. Junta de Andalucia, Consejeria indicaron su presencia en el pasado. La persecucion hu- de Medio Ambiente, Cadiz, Spain. mana puede ser la causa de esta disminucion. Al menos DEL Moral, J.C. and R. Mart! (Eds.). 2001. El buitre en el area de estudio la especie esta extinta como nidi- leonado en la Peninsula Iberica. SEO/BirdLife, Ma- ficante. Las recuperaciones de aves anilladas son escasas drid, Spain. Donazar, 1993. Los buitres ibericos: biologia con- y se concentran en tres zonas: el desierto del este, las J.A. y Ediciones, Madrid, montanas centrales y la Costa Atlantica de Marruecos. servacion. J.M. Reyero Spain. Son necesarias urgentes investigaciones sobre el estado , O. Cebaixos, a. Travaini, and E. Hiraldo. 1993. del buitre G. fulvus en todo el pais. Roadside raptor surveys in the Argentinean Patagon- [Traduccion de los autores] ia. /. Raptor Res. 27:106-110.

Elosegui, J. and R. Elosegui. 1977. Desplazamientos de Acknowledgments buitres comunes {Gyps fulvus) pirenaicos. Munibe 29 97-104. The travel was financed by Centro de Estudios Super- T. 1996. Suivi partiel de iores, Marcelo Spinola University of Wales from Umbrete Franchimont, j. and Moumni. la migration post-nuptiale des rapaces diurnes sur la (Sevilla) . Adolfo Rodriguez, Juan Jose Ramos Encalado, Angel Gomez-Manzaneque, and Patrick Bergier provided rive du sud du detroit de Gibraltar en 1995. Porphyno us with useful observations. Colin Pennycuick and Eiona 8:55-76.

Grant from Free Spirit Films (Bristol) greatly improved Fuller, M.R. and J.A. Mosher. 1981. Methods of detect- editor the English text. Peter Mundy and the provided ing and counting raptors: a review. Stud. Avian Biol. 6' helpful comments on an earlier draft of the manuscript. 235-246. Garrido, A. Camina, M. Surroca, and Mottos. Literature Cited J.R., J. 2001. Migration of the Eurasian Griffon Vulture {Gyps Alonso, J.C. 1984. Sur les quartiers d’hiver des vautors fulvus) through the Iberian Peninsula. Raptor Re- fauves migrateurs. Alauda 52:308-309. search Foundation and Estacion Biologica de Don- Arroyo, B., E. Ferreiro, and V. Garza. 1990. Segundo ana, Sevilla, Spain.

censo nacional de buitre leonado {Gyps fulvus)'. pob- Gomez-Manzaneque, A., F. Hernandez-Carrasquilla, O. lacion, distribucion, demografia y conservacion. Co- Corral, and R. Moreno-opo. 2002. Informe sobre la leccion Tecnica, Instituto Nacional para la Conserva- campana de anillamiento de aves en Espana. Ecologia cion de la Naturaleza, Madrid, Spain. 16:343-376.

Arthur, C.P. and D. Peyrusque. 2000. Compte-rendu de Griesinger, j. 1998. Juvenile migration and dispersion I'operation 1999 de marquage de vautours fauves among griffon vultures Gyps fulvus in Spain. Pages dans la reserve nature lie d'Ossau. Rapport PNP/ Ser- 613-622 in B.-U. Meyburg, R. Chancellor, andJ.J. Fer- 74 Short Communications VoL. 39, No. 1

rero [Eds.], Holarctic birds of prey: proceedings of SociEDAD Espanola de Ornitologia/BirdLife. 1981 an international conference. World Working Group Primer censo nacional de buitreras. Ardeola 26-27' on Birds of Prey and Owls, Badajoz, Spain. 165-312. activities Haddane, B. 1996. The impact of human and . 2001. Seguimiento de la migracion en el estre- rehabilitation of raptors: case study, current situation cho, ano 2000. Consejeria de Medio Ambiente Junta of raptors in Morocco. International Conference de Andalucia y Sociedad Espanola de Ornitologia, on Raptors 1996, The Raptor Research Foundation Madrid, Spain. and the University of Urbino, Urbino. Italy. Soto, P. 1986. Le statut du vautour fauve Gyps fulvus au Lavna, F.J. 1999. Eurasian Griffons Gyps migrating maroc. Birds Prey Bull. 3:173-181. into Cap Blanc, Mauritania, Western Sahara. Vulture Thevenot, M., J.D.R. Vernon, and P. Bergier. 2003. The News 36:35-36. birds of Morocco. British Ornithologists' Union, Lon- Mundy, P. 2000. The status of vultures in Africa during don, U.K. the 1990s. Pages 151-164 in R.D. Chancellor and B.- Valdes, B. 1991. Andalucia and the rif, floristic links and U. Meyburg [Eds.], Raptors at risk. World Working common flora. Bot. Chron. 10:117-124. Group on Birds of Prey and Owls, Berlin, Germany.

, D. Butchart, J. Ledger, and S. Piper. 1992. The vultures of Africa. Academic Press, London, U.K. Received 3 July 2003; accepted 8 December 2004

Artificial Nest Structure Use and Reproductive Success of Barn Owls in Northeastern Arkansas^

Paul M. Radley^ and James C. Bednarz Department of Biological Sciences, P.O. Box 599, Arkansas State University, State University, AR 72467 U.S.A.

Keywords: Barn Owl; Tyto alba pratincola; artificial nest- abundant. At this site, Marti et al. (1979) surveyed ca. 50 ing structures; breeding chronology; reproductive success; pro- silos that were used as roosts by Barn Owls, but only one ductivity; Arkansas. provided a suitable nest site. In 1977, these workers placed nest boxes in 30 silos before the spring nesting Raptor numbers and productivity in some regions are period. By the end of 1978, 24 (80%) of the boxes were clearly limited by availability of nest sites (Newton 1979). used by breeding owls (Marti et al. 1979). Similarly, on A shortage of nest sites may hold raptor populations at a oil palm {Elaeis guineensis) plantations in Malaysia, Duck- breeding density below the level that food would other- ett (1991) reported that breeding population densities of evi- wise support (Newton 1979). There are two types of the Barn Owl {T. a. javanica) were limited by available dence in the literature that support this hypothesis: (1) nest sites, despite high densities of several species of rat breeding pairs are scarce in areas where nest sites are {Rattus spp.; ca. 250-400/ha) . Twenty months after Duck- (but otherwise absent which seem suitable), and (2) the ett (1991) erected 200 nest boxes in a 1000 ha mature provision of artificial nest sites is often followed by an palm plantation (1 box/5 ha), 95% were occupied by increase in breeding density (Newton 1979). nesting Barn Owls. As a result, rat damage to palm trees Studies Barn Owls {Tyto alba) in northern done on on the plantation had dropped by 18.1% from the be- Utah by Marti et al. supports Newton’s (1979) (1979) ginning of the study (Duckett 1991). The studies con- proposal concerning the effect of limited nest sites. Marti ducted by Marti et al. (1979) and Duckett (1991) support et al. (1979) suggested that prior to the appearance of the hypothesis that Barn Owl populations can be limited buildings, a breeding population of Barn Owls was vir- by the availability of nest sites. tually nonexistent on his study area due to a paucity of Bloom and Hawks (1983) recorded similar results by suitable nest sites, but that foraging habitat and prey were testing nest-site limitation in American Kestrels {Falco sparverius) in northern California. Of a total of 208 nest

^ The editorial processing and review of this paper were boxes examined between 1977-80, 31% were occupied handled by Clint W. Boal. by breeding kestrels (Bloom and Hawks 1983). Bloom ^ Email address: [email protected] and Hawks (1983) suggested that with more strategic . .

March 2005 Short Communications 75

'-T»T» r 7

. D 1.1

D'd j d

Figure 1 . Location of Barn Owl study plots in Craighead and Poinsett counties, northeastern Arkansas, 2000 and

2001 .

placement of nest boxes, occupancy could easily have Figure 2. Details and dimensions (cm) of Barn Owl ar- reached 50%. Hamerstrom et al. (1973) reported similar tificial nesting structures placed in manipulated study results during a 5-yr study of nest box use by kestrels in plots, northeastern Arkansas, 2000. Wisconsin. We tested the hypothesis of nest-site limitation on a those in which we placed nest boxes) by the toss of a population of Barn Owls in northeastern Arkansas by coin and the remaining served as controls (Fig. 1 ) providing artificial nesting structures. To examine the ef- Artificial Nesting Structures. In winter 2000, upon re- fect that an increase in potential nest sites had upon the ceiving permission from landowners, we erected 12 nest- local population, we conducted our research on replicate ing boxes in each of the four manipulated study plots experimental and control plots. Although there is a (Fig. 1). We placed six nest boxes on man-made struc- wealth of data on reproductive success of Barn Owls in tures (i.e., grain bins, machine sheds, abandoned cotton gins) where there appeared to be relatively low levels of other regions (e.g., Marti 1992, Taylor 1994), there are , human activity. We secured the other six structures to no data for the species in Arkansas. Thus, another objec- isolated trees (i.e., natural structures) standing alone or tive of this study was to provide data on the reproductive in small aggregations (Bunn et al. 1982) in or along ag- success of Barn Owls in Arkansas and compare these re- ricultural fields. All nesting structures were placed be- sults with data from other areas. tween 2.4—6.8 m from the ground (man-made structures: X = 4.5 m, range = 2.5-6.8 m; trees: x = 4.0 m, range Methods 2.4-6.3 m). We began placing nest boxes on buildings Study Area. Our research was primarily conducted in and trees on 27 January 2000 and erected the last one a 1700-km^ study area in Craighead and Poinsett coun- on 7 March 2000. As data on Barn Owl nesting chronol- ties, northeastern Arkansas (35‘’30'-36°N, 90°20'-91°W; ogy were lacking for Arkansas, we based the timing of Fig. 1). These two counties were bisected north to south our placement of nest boxes on nesting chronology re- by a narrow zone of topographic relief known as Crow- ported from other studies (e.g., Marti 1994). Boxes were ley’s Ridge. To the west of this ridge, the agricultural placed no closer than 1000 m apart. Duckett (1991) sug- landscape of both counties was dominated by rice, soy- gested this spacing (>1000 m) to be adequate for nesting bean, and winter wheat. To the east of the ridge, these Barn Owls in most locations in Malaysia, as this species crops were mixed with cotton. is generally not territorial over its hunting areas. Within the study area we delineated eight study plots Artificial nest structures (design suggested by K. Rowe, (10 X 10 km) with similar cover types. The proportion Arkansas Game and Fish Commission, pers. comm.) were of agricultural cover in our study plots varied between constructed from 91.4 cm lengths of thick-wall (0.7 cm) 89.6-96.8% (x = 93.0%; based on ArcView Geographic polyvinyl-chloride (PVC) pipe, with an inside diameter of Information System [Environmental Systems Research 38.9 cm (Fig. 2). At the ends, we secured 1.3 cm thick Institute, Inc., Redlands, GA U.S.A.] analysis of USGS dig- plywood pieces, coated on both sides with Thompson’s ital orthophoto quadrangles [DOQs]). Four of these Water Seal (Memphis, TN U.SA.), and inset 2.5 cm from were east and four were west of Crowley’s Ridge (Fig. 1). the ends of the pipe. The plywood ends were secured The plots to the east of the ridge were covered primarily with 3.2 cm length drywall screws (four at each end), and by a relatively even mix of rice and cotton, with some the seam between the plywood ends and PVC pipe was winter wheat and soybean, while the plots to the west of sealed with black silicon caulking. To facilitate drainage, the ridge were dominated by rice with a small contingent we drilled three 1.3 cm holes in the bottom of the front of winter wheat and soybean. We designated two plots on half of each nest box (Fig. 2) either side of the ridge as “manipulated” areas (i.e.. Barn Owl Surveys. Between 15 March-9 April 2000 76 Short Communications VoL. 39, No. 1

and 10-24 April 2001, we searched all manipulated and Table 1. Number of Barn Owl nests located in separate control plots by day for signs of nesting owls. Likewise, study plots (each 100 km^) in northeastern Arkansas in artificial nesting structures, to determine occupancy of 2000 and 2001. we checked all plots in March and June 2000, and again m January, March, June, and September of 2001 (Loo- man et al. 1996). Number of Number of With permission from landowners, we visually inspect- Nests Nests ed all farm structures and abandoned cotton gins in all Study Plot Status'* IN 2000 IN 2001 plots for nests. When nests were found, we recorded the location, clutch size, and number of nestlings for each. Bay Control 1 2 Nests were monitored periodically until young reached Cash Control 0 0 fledging age (ca. 60 d after hatching; Marti 1992; data Egypt Control 0 0 presented below). Goobertown Control 0 0 extensive auditory surveys of all manip- We conducted Lepanto Manipulated 2 6 ulated and control plots between 26 April-4 June 2000, McCormick Manipulated 2 2 and again between 24 May-13 June 2001. We conducted Otwell Manipulated 1 1 surveys at night from roads within the study plots. Roads Waldenburg Manipulated 0 0 were well distributed, primarily at 1.6 km intervals along section lines throughout all plots. We stopped at all hu- ®We errected 12 artificial nest structures in each manipulated man-developed structures suitable for owl use (barns, cot- plot between January and March 2000. No artificial structures ton gins, etc.) and woodlots with snags, and listened for were placed in control plots. juvenile food begging calls and adult contact calls for 8- 10 min/site. To accomplish this, we used a Seinnheiser microphone mounted on a 46 cm parabolic reflector study plots (Fig. 1), In 2000, 11 Barn Owl nests were (Saul Mineroff Electronics, Elmont, NY U.S.A.; Colvin In season, eight nest 1984). With this equipment, begging and contact calls discovered. the 2001 of the 2000 could typically be detected from a distance of ca. 0.5 km. sites were again in use and eight new nest sites were lo- All roads in each of the eight study areas were systemat- cated. Seventeen of the 27 nests were in four of the eight ically searched. For the reproductive success study, we study plots (Table 1). These nests included four in our also monitored nests located off plots. These were either nest boxes, nine located by nest searches and checking brought to our attention by landowners, or were found historical sites, and four in wooden nest boxes erected by when searching appropriate looking sites such as old landowners prior to our study. grain elevators, cotton gins, and wooden barns. Of the nests found in the four study plots, three were We used the Mayfield Method (1975) to estimate relocated in control plots (x = 0.75) and 14 were in ma- productive success. Because of other research objectives, plots (x = In nest was frequency of nest visits were periodic and varied between nipulated 3.5; Table 1). 2000, one 2-30 d intervals (typically 10-20 d intervals). For this found in a control plot (Bay) and five were located in analysis, we assumed an incubation period of 30.8 d, with three manipulated plots (Lepanto, McCormick, and 2 3d between egg-laying (Marti 1992). As we could rea- Otwell). In 2001 we found two nests in the same control sonably estimate a mean brood-rearing period (v = 59.7; plot and nine in the same three manipulated plots (Table range = 52-67 d) for 10 nests that fledged young in our 1 ). study area, we used 60 d as the brood-rearing interval for Ten other nests were found off study plots (Fig. 1), all nests included in the Mayfield analysis. We did not four of which were reported to us by landowners (Radley include nests that were found after they failed (e.g., with 2002). Two nest sites were located at the Craighead abandoned eggs) in this analysis. County Fairgrounds in the city ofJonesboro, and the re- Results mainder were in agricultural areas adjacent to established plots. Eight of these nests were at sites occupied Nest Boxes. Of the 48 nest boxes erected, four (8.3%) by nesting owls in both 2000 and 2001; four nests were were occupied by owls before the end of the study (a located in two wooden nest boxes, two nests were in a period of ca. 19 mo) . All four of these nesting boxes had tree cavity in successive years, and two were found in an been erected on man-made structures (i.e., pole or ma- old grain elevator located south of the Otwell plot (Fig.

chine sheds). On 23 June 2000, a roosting Barn Owl was 1 ) . Of the last two nests, one was located on a roof truss flushed from a box placed on a machine shed in the of an open shed, and one was in the hay loft of a horse Lepanto study plot (Fig. 1). In January 2001, this .same barn. No previously unrecorded nests were located in any box was found to be occupied by a nesting owl that was plot by the auditory surveys. incubating eggs and later produced two young. In March Breeding Chronology and Reproductive Success. Al- 2001, three other nest boxes on the Lepanto study plot though Barn Owls may produce more than one brood were occupied by breeding owls, all of which failed be- per year (Lenton 1984, Marti 1994), we detected no sec- fore any young fledged. No nest boxes erected on trees ond broods during our study. To determine the onset of were occupied by Barn Owls during our study. egg laying, we backdated from the date of fledging for Nesting. We found a total of 27 nests on and off our each nest. Based on a total of 13 nests that fledged young March 2005 Short Communications 77

in 2000 and 2001, the mean date of the onset of egg On our study area as a whole, however, relatively few laying for Barn Owls in our study area was 15 February nesting structures were occupied by the time we com- (median = 14 February; range = 9 January-22 March). pleted field monitoring in December 2001. Also, no sign The earliest date that eggs were actually observed in nests of use (e.g., pellets) was observed at any of the other was 8 February and the latest was 5 April. The length of structures. It is possible that the local Barn Owl popula- the nesting season (defined here as the period from the tion was limited by some other environmental factor onset of first egg laying to fledging of the last young) for (e.g., prey availability, juvenile mortality) leading to low the Barn Owl population in our study area averaged 5.8 occupancy of nest boxes in northeastern Arkansas. mo over the 2 study years. Breeding Chronology and Reproductive Success. The Of the 11 Barn Owl nests found in 2000, six success- mean date of the onset of egg laying for Barn Owls over fully fledged young (55%), two failed, and the fates of a 2-yr period in our study area in northeastern Arkansas three were undetermined. Mean clutch size was 4.5 eggs was 15 February. In comparison, the mean clutch initia- (range = 3-6, N = 8) and mean number of young tion date for Barn Owls in Utah was 13 March (Marti fledged per successful nest was 3.0 (range = 1-4, N = 1994). The latter estimate was based on a sample of 295 6). Fledging dates ranged from 6 April-10 July {x = 12 nesting attempts (first brood) over a 16-yr period. Also

May, median = 23 May). in Utah, Looman et al. (1996) reported that most owl In 2001, we found 16 nests, eight of which were at sites pairs attempting first clutches (36%) commenced egg that had been used in the previous season. Of the oc- laying in the first half of March, while 25% began in late cupied nests, seven fledged young (47%), eight failed, February. Based on a sample of 100 Barn Owl nests m and the fate of one could not be determined. Mean New Jersey, Colvin (1984) gave 14 April as the mean peak clutch size was 3.1 (range = 1-5, N = 9) and mean num- of egg laying. The mean length of the nesting season for ber of young fledged per successful nest was 2.6 (range Barn Owls in our study was 5.8 mo over the 2 study yr. = 1-4, N = 7). Fledging dates of the eight successful In comparison, Otteni et al. (1972) reported 5.3 mo over nests ranged from 18 May-5 July (x = 6 June, median = a 7-yr period in south Texas, while Looman et al. (1996) 11 June). Mean clutch size for the 2 yr was 3.8 (N = 17) gives 6.6 mo as the mean for a 5-yr study in north-central and mean number of young fledged per successful nest Utah. Barn Owl nesting success in our study (56%) was was 2.8 (N = 13). Our Mayfield (1975) estimate of Barn similar to Barn Owls in the Chesapeake Bay area of Mary- Owl nesting success (defined here as the probability of land (57%; Reese 1972), but slightly lower than that re- survival of a nest from the start of incubation to the fledg- ported in south Texas (66%; Otteni et al. 1972). ing of young) was 0.56 for 23 Barn Owl nests. Based on our data, we concluded that Barn Owls m Arkansas produce smaller clutches and fledge fewer Discussion young per nesting attempt compared to Barn Owls m

Artificial Nesting Structures. The lack of use of our most other parts of the world (Table 2). Lower clutch nest boxes in 2000 (no nesting, but one owl documented size and reproductive success of owls in Arkansas may be as roosting) was probably because most were not erected explained, in part, by the well established relationship until after many breeding Barn Owls had already selected between latitude and clutch size (Welty and Baptista nesting locations. Owls in our study area typically initi- 1988). However, several investigators (Otteni et al. 1972, ated nesting in mid-February. However, most of our nest- Lenton 1984, Wilson et al. 1986) working in areas at con- ing structures were not in place until mid to late Febru- siderably lower latitudes reported larger mean clutch siz- ary. When we initiated this study, there were no data es than those in our study (Table 2). Likewise, these same available pertaining to nesting chronology of Barn Owls investigators reported larger mean clutch sizes than those m Arkansas and we attempted to erect boxes before an- given by Taylor (1994) in Scotland and Bunn et al ticipated nesting in March and April. Because owls start- (1982) in England. ed breeding earlier than the original estimated dates for There is evidence in the literature that clutch size and nesting, they may not have had adequate time to find fledging success in Barn Owls are related to prey avail- and to habituate to the structures for nesting in 2000. ability and habitat (both of which can vary locally and

In 2001, all four nest boxes used by breeding owls were temporally) as well as other variables associated with lat- located on man-made structures (i.e., pole or machine itude. For example, Otteni et al. (1972) reported that the sheds) in the Lepanto study plot. Based on casual encoun- mean clutch size, number of fledglings, and nest success ters with owls, this plot appeared to have a high density of all decreased markedly following a dramatic decline in Barn Owls (both breeding and nonbreeding individuals) rodent numbers. Marti and Wagner (1985) found the before the nesting structures were erected. However, we number of young fledged per pair of Barn Owls in north- had no data pertaining to Barn Owl densities on this plot ern Utah varied from 3. 6-4.8 until 1982, when it fell to prior to treatment. The fact that artificial nest structures 1.6 following an extremely severe winter that may have were exploited in the Lepanto plot, which appeared to reduced local vole populations. In Scotland, Taylor have a high number of owls to begin with, suggests that (1994) noted that clutch sizes and fledging success were suitable nesting sites in this area may have been limited. closely correlated with annual, cyclic variations in vole 78 Short Communications VoL. 39, No. 1

Table 2. Mean clutch sizes and number of young fledged for Barn Owl populations in different geographic areas.

Mean No. of Young Mean Clutch Fledged Per Geographic Location Latitude Size (A) Successful Nest (A) Source

North-central Utah 41°N 7.2 (275) 5.1 (220) Marti 1994 Peninsular Malaysia 2°55'-l°I6'N 6.6 (36) 3.7 (33) Lenton 1984 Central Mali, Africa 14°I5'N 6.1 (140) 3.2 (78) Wilson et al. 1986 North-central Utah 39°-40°N 5.8 (85) 3.9 (104) Looman et al. 1996 Chesapeake Bay, Mary- land ~38°N 5.5 (74) 3.8 (42) Reese 1972

South-central Illinois 38°45'N 5.2 (5) 3.8 (5) Walk et al. 1999 Southwest New Jersey 39°45'N Not reported 3.8 (125) Colvin 1984 Southern Texas 28°N 4.9 (91) Not reported Otteni et al. 1972 England ~54°N 4.7 (178) Not reported Bunn et al. 1982 Scotland 55°-56°N 4.6 (425) 3.1 (490) Taylor 1994 Northeast Arkansas 35°30'-36°N 3.8 (17) 2.7 (14) This study Santa Cruz Island, Gala- pagos 0°-l°S 3.1 (10) 1.6 (10) De Groot 1983

{Microtus spp.) abundance. Taylor (1994) also found that reproductivo en el noreste de Arkansas durante 2000—01 cover types near the nest site affected clutch size and Se delinearon ocho parcelas de estudio (cada una de 100 fledging success. Barn Owl pairs that nested in or near km^) que incluian principalmente cultivos de arroz, trigo tree plantations produced mean clutch sizes of 5.1 eggs de invierno, soya y algodon. Aleatoriamente, cuatro de (range = 4. 0-6. 7), whereas those in low farmland yielded estas parcelas fueron designadas como controles y cuatro mean clutches of 4.0 eggs (range = 3. 0-6.0), but differ- como areas “manipuladas”, en cada una de las cuales se ences between areas were greatest in vole peak years erigieron 12 estructuras de nidificacion (A = 48 estruc- (Taylor 1994). Thus, in Scotland it would appear that turas) entre enero y marzo de 2000. Una de las estruc- cover type affects prey availability, which in turn, influ- turas fue ocupada como percha dormidero por un indi- ences Barn Owl productivity. viduo en junio de 2000 y cuatro (8.3%, N= 48) fueron In light of these findings, the poor nest productivity ocupadas por individuos nidificantes en marzo de 2001. for Owls in northeastern Arkansas may we recorded Barn Encontramos 27 nidos tanto dentro como fuera de las due to a relatively low prey base resulting from be parcelas de estudio, de los cuales 14 estuvieron en las drought-like conditions that the state had been under for parcelas manipuladas (x = 3.5 nidos/ parcela) y tres en the better part of our study (S. Culp, Craighead County las parcelas control (x = 0.75 nidos/parcela). De 14 m- Extension Office, pers. commun.). However, we have no dos salieron un total de 38 pichones, 10 nidos fracasaron data on local prey availability or abundance for the 2 yr y el destino de tres no fue determinado. La fecha pro- of our study to examine these hypotheses, and recom- medio de iniciacion de la postura por parte de T. alba en mend that sampling to determine mammal abundance nuestra area de estudio fue el 15 de febrero (mediana = would be important to understand factors that may influ- 16 de febrero; rango = 28 de diciembre — 25 de marzo), ence the variation in reproductive success. Also, our la duracion promedio de la estacion de nidificacion, study was relatively short term, and it is likely that Barn y desde el comienzo de la postura de huevos hasta el em- Owl productivity in northeastern Arkansas may fluctuate plumamiento del ultimo pichon, fue de 5.8 meses. El over the long term with variations in prey populations. promedio fue = el nu- Additional data, collected over more years of study, would tamano de nidada 3.8 {N 17) y por nido exi- be needed to evaluate this possibility. Finally, because mero promedio de pichones emplumados most of the nests in our study were in some form of nest toso fue 2.7 {N = 14). La productividad de los nidos de box, our data may not be directly comparable to studies T. alba en nuestro estudio fue considerablemente menor involving natural nest locations (i.e., tree cavities). que la reportada por otros estudios sobre esta especie realizados alrededor del mundo. El pobre desempeno re- Uso DE Estructuras de Nidificacion Artificiales y productivo pudo haberse debido a que los tamanos de

Exito Reproductivo de Tyto alba en el Noreste de las poblaciones de presas eran relativamente pequenos Arkansas debido a las condiciones de sequia sufridas por la region Resumen.—Colectamos datos sobre el uso de cavidades del noreste de Arkansas durante el estudio. de nidificacion por parte de Tyto alba y sobre su exito [Traduccion del equipo editorial] March 2005 Short Communications 79

Acknowledgments Marti, C.D. 1992. Barn Owl {Tyto alba). In A. Poole, P. Major funding was provided by the Arkansas Game and Stettenheim, and F. Gill [Eds.], The birds of North Fish Commission and was facilitated by Karen Rowe. Ad- America, No. 1. Academy of Natural Sciences, Phila- ditional monetary support was contributed by the Arkan- delphia, PA and the American Ornithologists’ Union, sas Audubon Society Trust. The Keeling Co. of Jones- Washington, DC U.S.A. boro, Arkansas, gave a generous reduction on the price . 1994. Barn Owl reproduction: patterns and var- of the PVC pipe necessary to build artificial nesting struc- iation near the limit of the species’ distribution. Con- tures. We thank J.D. Wilhide, V. Hoffman, C.J. George, J. dor 96:468-484. Holt, T. Bader, B. Cannon, M. Cannon, D. Ripper, L. 1985. mortality in Wilf, M. Barnett, C. McCown, K. Levenstein, L. Alterman, and P.W. Wagner. Winter com- and D. Feldman for assistance in the field. Also, we thank mon Barn Owls and its effect on population density all the landowners who gave us permission and access to and reproduction. Condor S7\\W— 11b. their lands. We greatly appreciate the contributions of , , AND K.W. Denne. 1979. Nest boxes for Eric Forsman, who reviewed an earlier draft of this man- the management of Barn Owls. Wildl. Soc. Bull. 7:145- uscript. Lastly, like to thank C. Boal, M. Martell, we would 148. and two anonymous reviewers for their valuable sugges- Mayfield, H.F. 1975. Suggestions for calculating nest suc- tions and constructive editing of this manuscript. cess. Wilson Bull. 87:456-466.

Literature Cited Newton, 1. 1979. Population ecology of raptors. T. & A.D Poyser, London, U.K. Bloom, RH. and SJ. Hawks. 1983. Nest box use and re- Otteni, L.C., E.G. Bolen, and C. Cottam. 1972. Preda- productive biology of the American Kestrel in Lassen tor-prey relationships and reproduction of the Barn County, California. Raptor Res. 17:9-14. Owl in southern Texas. Wilson Bull. 84:434—448. Bunn, D.S., A.B. Warburton, R.D.S. Wilson. 1982. The Radley, P.M. 2002. Artificial nest structure use, post- Barn Owl. Buteo Books, Vermillion, SD U.S.A. fledging habitat use, and dispersal of Barn Owls {Tyto Colvin, B.A. 1984. Barn Owl foraging behavior and sec- alba pratincola) in the Delta region of Arkansas. M.S. ondary poisoning hazard from rodenticide use on thesis, Arkansas State Univ., Jonesboro, AR U.S.A. farms. Ph.D. dissertation, Bowling Green State Univ., Reese, J.G. 1972. A Chesapeake Barn Owl population. Bowling Green, OH U.S.A. Auk 89:106-114. De Groot, R.S. 1983. Origin, status and ecology of the Taylor, I. 1994. Barn Owls: predator-prey relationships owls in Galapagos. Ardea 71:167-182. and conservation. Cambridge University Press, Cam- Duckett, J.E. 1991. Management of the Barn Owl {Tyto bridge, U.K. alba javanica) as a predator of rats in oil palm {Elaeis Walk, J.W., T.L. Esker, and S.A. Simpson. 1999. Contin- guineensis) plantations in Malaysia. Ends Prey Bull. 4: uous nesting of Barn Owls in Illinois. Wilson Bull. 111. 11-23. 572-573. Hamerstrom, R, F.N. Hamerstrom, and J. Hart. 1973. Welty, J.C. and L. Baptista. 1988. The life of birds. 4th Nest boxes: an effective management tool for kestrels. Ed. Saunders College Publishing, New York, NY J. Wildl. Manag. 37:400-403. U.S.A. Lenton, G.M. 1984. The feeding and breeding ecology Wilson, R.T., M.P. Wilson, and J.W. Durkin. 1986 of Barn Owls ( Tyto alba) in peninsular Malaysia. Ibis of {Tyto alba) 126:551-575. Breeding biology the Barn Owl in central Mali. Ibis 128:81-90. Logman, S.J., D.L. Shirley, and C.M. White. 1996. Pro- ductivity, food habitats, and associated variables of Barn Owls utilizing nest boxes in north central Utah. Received 21 October 2003; accepted 17 November 2004 Great Basin Nat. 56:73—84. Associate Editor: Clint Boal J. Raptor Res. 39(1):80—83 © 2005 The Raptor Research Foundation, Inc.

Abundance and Diet of Alexander’s Kestrel (Falco tinnuncmlus alexandri) ON Boavista Island (Archipelago of Cape Verde)

Diego Ontiveros

Departamento de Biologia Animal y Ecologia, Facultad de Ciencias, Universidad de Granada, E-18071 Granada, Spam

Key Words: Common Kestrel, Falco tinnunculus alexan- comprised of 10 islands and several islets. Boavista Island ca. dri; diet, abundance, Boavista; Alexander’s Kestrel, extends 620 km®, with 116 km of perimeter, being the third largest island of the archipelago in surface area. Its

topography is generally flat; the highest elevation (Monte Alexander’s Kestrel {Falco tinnunculus alexandri) is an Estancia) is 387 m. The climate is very dry (mean annual endemic resident subspecies of the Kestrel re- Common rainfall = 91 mm; Kasper 1987) and the presence of siding on Cape Verde archipelago, characterized by goats causes continued desertification of the land. There- heavily marked upper parts and a barred tail in all plum- fore, the landscape of the island consists mainly of large ages (Hazevoet 1995), which occurs only on the eastern areas covered with sand, forming mobile dunes and bar- and southern islands (Sal, Boavista, Maio, Santiago, Fogo, ren-stony plains, but in the interior there are oases with palms (Sena-Martins et al. 1986). Because the moderat- and Brava) . The geographical distribution of the subspe- ing influence of the surrounding ocean temperatures are cies in the archipelago is explained by the effect of the relatively constant, the amplitude of mean temperatures last glaciation, which split the kestrel population into two in different months seldom exceed 6°C. distinct island groups, with Alexander’s Kestrel to the To estimate the abundance of Alexander’s Kestrels on south and Neglectus Kestrel {Falco tinnunculus neglectus) Boavista Island, a driver and an observer performed sev- to the north (Hazevoet 1995). This circumstance caused en line transects (one transect/d) in a vehicle during July morphological and ecological differences between the 1999, on days of good visibility, travelling at ca. 40 km/ two subspecies of raptors (Hille and Winkler 2000), hr, counting (with 10X40 binoculars) all individuals which are endemic birds scarcely known at present. perched or flying closer than 300 m on either side of the lengths 9-55 (to- Alexander’s Kestrel is common on the islands, occu- road. Transect varied, ranging from km tal length = 226 km) according to the availability of ad- pying all habitats from sea level up to the highest moun- equate roads. All censuses were performed on unpaved tains, but information on its biology is lacking. Only its roads, far from the few existing power lines (potential taxonomy, distribution, and breeding dates have been re- hunting perches) of the island, these being located in ported (Bourne 1955, De Naurois and Bonnaffoux 1969, villages; therefore, the data are not biased by this circum- Stresemann and Amadon 1979, De Naurois 1987, Haz- stance. Counting raptors from a vehicle along roads in a evoet 1995), but no data are available on its abundance flat landscape with scarce vegetation (the case for Boa- or food habits in the archipelago. vista Island) is a widely used method (Johnson 1978, Ful- Islands offer divergent environments with geographi- ler and Mosher 1981, Byby et al. 2000), particularly for cally separated animal populations that are subject to sev- kestrels (Telia and Forero 2000). It provides an abundance index that is sensitive to the behaviour of the spe- eral evolutionary forces such as genetic bottle-necks, cies involved, the habitat surveyed, speed of the vehicle, drift, gene flow, and selection driven by local conditions. meteorological conditions, hour, season, and number In this way, the conservation needs of island fauna, and and experience of observers. In the presence of the ob- especially of raptors, are generally more urgent than server, the animal response varies according to different continental species, except limited distri- those of where factors (Eberhardt 1978, Burnham et al. 1980). There- butions on continents mimic island-like isolation (Virani fore, in the censuses I considered the detection distance 1995, Virani and Watson 1998). Therefore, knowledge of and angle of individuals. Boavista Island has a homoge- an endemic and restricted species such as Alexander’s neous landscape (desert with some oases), and the line transects Kestrel is key to their conservation. length of the were distributed proportionally over the surface of these habitats. I estimated the In this paper, I present the first data on the relative density of Alexander’s Kestrel on the island with the pro- abundance and diet composition of Alexander’s Kestrel gram DISTANCE 4.1 (Thomas et al. 1998) and empiri- on an island (Boavista), which represents 23.5% of the cally calculated the variance. distribution area of the subspecies in the world. Also, I studied the food habits of this raptor in July, analyzing 44 pellets collected under eight different roost- Study Area and Methods ing sites. Due to the scarce number of bird species on The Cape Verde Islands are situated in the eastern At- the island (see Discussion), avian prey were identified lantic, between 14°48'-17°22'N and 22°44'-25°22'W, from feather remains when possible, reptiles from skulls 460-830 km west of Senegal (Fig. 1). The archipelago is and mandibles collected from the study area, mammals from hair remains (Teering and insects from head 1991) , capsules and mandibles. The biomass contribution of ^ Email address: [email protected] each species in the total biomass was estimated following

80 March 2005 Short Communications 81

estimated during my surveys. Nevertheless, the limited 100 km sample size of this study requires caution in the interpre- tation of results.

Although Boavista Island is topographically flat and practically deforested (Diniz and Matos 1988), the kes- Boavista trels were invariably located in areas with trees, buildings Island or small cliffs, and were never found in areas without perch and roost habitat. The availability of elevated o perches could favour prey detection, especially small ground-dwelling lizards.

In fact, based on the pellet analysis an endemic skink, Mabuya spinalis salensis, accounted for the 84.7% of the

1 . of Verde Islands, and their position Figure Map Cape biomass consumed by Alexander’s Kestrel. This small liz- relative to West Africa. ard has a mean mass of 11.8 g (J.A. Mateo pers. comm ), close to the mean biomass (10.6 g) of 72 total prey items found in the pellets (Table 1). These results agree with Marti (1987), assigning the biomass of birds from Cramp other studies that have reported 12.01 g as a mean bio- (1998), and using mass data from individuals of the study mass of prey caught by Common Kestrels (Piatella et al. area for other prey. 1999). Boavista Island has a homogeneous semiarid cli- Results and Discussion mate throughout the year (Kasper 1987) and the lizards are active all year. Thus, this prey item may be important Analysis of the data collected with program DISTANCE in other seasons, as well as in July when I collected pel- showed a mean density of 0.125 Alexander’s Kestrels/ lets. km^ (95% C.I. = 0.045-0.348 kestrels/km^), implying an Several factors can explain the stenophagy of Alexan- estimated population of 77 individuals (95% C.I. = 28- der’s Kestrel on the Mabuya Skink on Boavista Island. (1) 216 kestrels) of Alexander’s Kestrel for Boavista Island. Only between 17-23 species of birds breed on the island However, I only detected seven kestrels (one male and (Hazevoet nine of which are smaller than Alex- SIX females), thus the estimated density must be consid- 1995), ander’s Kestrel, thus being potential prey. Among ered as a very course estimate. Burnham et al. (1980) (2) of turtles four liz- suggested that at least 40 detections were required to de- reptiles, only two species marine and termine adequate density estimates using line transects ards are present on the island (Lopezjurado et al. 1999), lizards techniques. but three of the are nocturnal ( Tarentola and Hem- Most young Alexander’s Kestrels leave their nests in idactylus) and only the skink is diurnal, and may be the April (Hazevoet 1995), 3 mo before the censuses were primary prey of the kestrel. (3) As expected for an oce- performed (July). Therefore, the young were likely uni- anic island, no indigenous terrestrial mammals inhabit formly distributed throughout the island. Thus, the total the Cape Verde Archipelago, and only the exotic Mus breeding population might be lower than the numbers musculus and Rattus spp. are present (Hazevoet 1995),

Table 1. Dietary composition of the Alexander’s Kestrel on Boavista Island (Cape Verde).

Frequency Biomass Prey N{%) g (%)

Aves

Bar-tailed Desert Lark {Ammomanes cincturus) 2 (2.8) 34.8 (4.5) Unidentified passerines 3 (4.2) 45 (5.9)

Reptilia

Skink {Mabuya spinalis salensis) 55 (76.4) 649 (84.7) Mammalia

House mouse {Mus musculus) 1 (1.5) 21 (2.7)

Insecta

Grasshopper {Heteracris sp.) 10 (13.9) 15 (2)

Unidentified Coleoptera 1 (1.5) 1 (0.1) Total prey 72 82 Short Communications VoL. 39, No. 1

but quite scarce in a sparsely human populated area such measures to preserve the rapidly declining populations as Boavista. (4) Finally, the sparse vegetation of the island of seabirds and endemic land birds of Cape Verde Islands does not support great numbers of invertebrates, which (e.g., De Naurois 1964, Norrevang and Hartog 1984, Har- therefore barely appear in the diet of the kestrel. Con- tog 1990, Donald et al. 2003). The stenophagy of the sequently, the only prey species on Boavista Island that is Alexander’s Kestrel, the scarcity of elevated perches and largely abundant, a ground dweller, appropriate in size, roosts, and the progressive deforestation of Boavista Is- and exhibits diurnal activity is the skink. The pellet data land, could affect the current status of this subspecies on clearly supports that the skink is the most common prey Boavista Island. of the Alexander’s Kestrel in July (Table 1). Nevertheless, the more easily digested prey, such as invertebrates, are AbUNDANCIA Y DiETA de FaLCO riNNUNCULUS ALEXANDRA EN often underrepresented in pellets (Mersmann et al. 1992, Lsla Boavista (Archipielago de Cabo Verde) Whalen et al. 2000) and therefore may be underrepresented in my results as well. Resumen.—El cernicalo Falco tinnunculus alexandri es una Many ecomorphological studies have shown the close subespecie de cernicalo comun, endemica del Archipie- relationship between habitat and behaviour of birds lago de Cabo Verde y escasamente conocida. En este ar-

(Leisler et al. 1989, Gamauf et al. 1998, Hille and Winkler ticulo se presentan los primeros datos sobre abundancia ground-level vegetation affect the abil- alimentacion de la rapaz en el archipielago, concreta- 2000) , and as can y ity to detect prey, this factor may influence the success of mente de la poblacion de la Isla de Boavista. Para su particular foraging behaviours (Bechard 1982, Janes estudio se han recorrido un total de 226 km de transectos 1985). Therefore, the broad deforestation of Boavista Is- lineales, cifrandose la poblacion de la especie en Boavista land and the absence of alternative prey could account en 0.125 individuos/km^ (95% I.C. = 0.045-0.348 individuos/km^) 77 individuos, si bien tomar for the high kestrel use of this .swift, but abundant, skink. , unos hay que Despite the limited sample size of this study, no other la cifra con precaucion ante lo reducido de la muestra studies on food habits of Alexander’s Kestrels in Cape obtenida. En la dieta de la rapaz unicamente se encon- Verde archipelago are available. Except for the re.sults of traron seis tipos de presas distintas, debido probable- this study, lizards have been reported as scarce prey in mente a la deforestacion general de la isla y escasa dis- the diet of the Common Kestrel throughout the western ponibilidad de recursos troficos. Su dieta se baso Palearctic (Cramp 1998). fundamentalmente en el consumo de Mabuya spinalis sal- These results contradict the prediction of Hille and ensis, un escincido endemico de la isla que represento Winkler who found that the larger bill and long- hasta el 84.7% de la biomasa comsumida por el cernicalo. 1993) (2000), er wing of Alexander’s Kestrel may indicate frequent ae- La acusada estenofagia de esta especie y la creciente es- rial hunting of larger prey items than those sought by the casez de perchas en la isla, podrian ser una amenaza para

Neglectus Kestrel. Nevertheless, aerial hunting is more el future de la poblacion del cernicalo F, tinnunculus al- energetically expensive and is employed in areas where exandri en esta isla. 1994) climatic and topographic conditions are conducive to [Traduccion de los autores] such foraging, or when prey availability is high enough to yield a positive energy budget (Barnard 1986, van Zyl Acknowledgments

. In support of this hypothesis, , a comparison of the I wish to thank J.M. Pleguezuelos and two anonymous diet of kestrels between South Africa and Europe showed referees for reviewing the original manuscript and pro- that the African population consumed mostly inverte- viding valuable suggestions, J.A. Mateo for mass data for Lopezjurado, F. Pascual, and the brates and lizards and only few mammals and birds, rath- specimens, and L.E people of Boavista for their kind help during this study. er than the opposite as observed in Europe (van Zyl

. Literature Cited The Cape Verde Islands are oceanic islands with a recent volcanic origin, and consequently have flora and Barnard, P. 1986. Wind-hovering patterns of three Afri- fauna derived from elsewhere. Oceanic islands are often can raptors in montane conditions. Arrfm 74:151-158 isolated laboratories on which their populations gave rise Bechard, M.J. 1982. Effect of vegetative cover on forag- to a marked radiation of different species. Contrary to ing site selection by Swainson’s Hawk. Condor 84:153- other islands widely studied, such as the Galapagos ar- 1.59. chipelago, the avifauna of Cape Verde is poorly known. Bourne, W.R.P. 1955. A new race of kestrel from the

The lack of study is especially troubling, because the oc- Cape Verde Islands. Bull. Br. Ornithol. Club 75:35—36. currence of Palearctic taxa in the Cape Verde is of con- Burnham, K.P., D.R. Anderson, and J.L. Laake. 1980. Es- siderable interest. These are the southernmost and most timation of density from line-transect sampling of bi- isolated breeding populations of some Palearctic species, ological populations, Wildl Monogr. 72:1-202. being some 2000 km from their nearest congeners in Byby, J.C., N.D. Burgess, D.A. Hill, and S. Mustoe. 2000 North Africa and Southern Europe (Hazevoet 1995). For Bird census techniques. Academic Press, London, almost 40 yr, scientists and naturalists have called for U.K. ,

March 2005 Short Communications 83

Cramp. S. 1998. The complete birds of the western Pa- Marti, C.D. 1987. Raptor food habit studies. Pages 67- learctic. Univ. Oxford Press, Oxford, U.K. 80 in B.A. Giron, B.A. Millsap, K.W. Cline, and D.M. De Naurois, R. 1964. Les oiseaux des iles du Cap Vert: Bird [Eds.], Raptor management techniques manual suggestions en vue de leur sauvegarde. Garcia de Orta National Wildlife Federation, Washington, DC U.S A

12:609-619. Mer.smann, T.J., D.A. Buehler, J.D. Fraser, and J.K D.

. 1987. Contribution a la connaisance de Seegar. 1992. Assessing bias in studies of Bald Eagle I’ecologie de la crecerelle (Falco tinnunmlus lanne) food habits./. Wildl. Manag. 56:73-78. dans I’archipel du Cap Vert. BoL Mus. Reg. Sci. Nat. Ndrrevang, a. and J.C. Hartog. 1984. Bird observation Torino 5:195—210. in the Cape Verde Islands (4-22 June 1982). Cour. For- AND D. Bonnaffoux. 1969. L’avifaune de Pile du schungsinst. Senckenb. 68:107-134. Sel (ilha do Sal, archipel du Cap Vert). Alauda 37:93- PiATELiA, E.L., A. Salvaii, A. Manganaro, and S. Eat- 113. TORlNi. 1999. spatial and temporal variations in the Diniz, A.C. AND G.C. Matos. 1988. Carta de zonagem diet of the Common Kestrels {Falco tinnunculus) in agro-ecologica e da vegetagao de Cabo Verde IV- Ilha urban Rome, Italy./. Raptor Res. 33:172-175. de Boavista. Garcia de Orta 10:49-72. Sena-Martins, D.A., J.M. Moreno, and J.M. Gomes. 1986. Donald, P.F., M. De Ponte, M.J. Pitta, and R. Taylor. La desertification aux ilex du Cap-Vert. Ministry of 2003. Status, ecology, behaviour and conservation of Rural Development and Fisheries, Praia, Cape Verde Raso Lark Alauda razae. Bird Conserv. Int. 13:13-28. Stresemann, E. and D. Amadon. 1979. Order Falcom-

Eberhardt, JJ- 1978. Transect methods for populations mes. Pages 271-425 in E. Mayr and C.W. Cottrell studies./. Wildl. Manag. 42:1-31. [Eds.], Check-list of birds of the world. Vol. I. Muse- Fuller, M.R. and J.A. Mosher. 1981. Methods of detect- um of Comparative Zoology, Cambridge, MA U.S.A

ing and counting raptors: a review. Pages 235-246 in Teering, B.J. 1991. Hair of West-European mammals

C.J. Ralph and J.M. Scott [Eds.], Estimating numbers Cambridge University Press, Cambridge, U.K. of terrestrial birds: studies in avian biology. Vol. 6. Teiia, J.L. AND M.G. Forero. 2000. Farmland habitat se- Cooper Ornithological Society, Lawrence, KS, U.S.A. lection of wintering Lesser Kertrels in a Spanish pseu- Gamauf, a., M. Preleuthner, and H. Winkler. 1998. dosteppe: implications for conservation strategies. Bio- Philippine birds of prey: interrelations among habitat, divers. Comerv. 9:433-441. morphology, and behaviour. Auk 115:713-726. Telleria, J.L. 1986. Manual para el censo de los verte- Hartog, J.C. 1990. Birds of Cape Verde Islands: notes on brados terrestres. Ed. Raices, Madrid, Spain.

species observed (9 August-10 September 1986), dis- Thomas, L., J.L. Laake, J.F. Derry, S.T. Buckiand, D.L. tribution, migration, status, origin and conservation. Borchers, D.R. Anderson, K.P. Burham, S. Strind-

Cour. Forschungsinst. Senckenb. 129:159-190. berg, S.I.. Hedley, M.L, Burt, E. Marques, J.H. Poi-

Hazevoet, C.J. 1995. The birds of the Cape Verde Is- iard, and R.M. Fewster. 1998. DISTANCE 4.1. Re- lands. British Ornithologists’ Union, Dorchester, U.K. search Unit for Wildlife Population Assessment, Univ

Hille, S. and H. Winkler. 2000. Ecomorphology of is- St. Andrews, St. Andrews, U.K.

land populations of the kestrel Falco tinnunculus on van Zyi^, A.J. 1993. Foraging of the South African kestrel Cape Verde. Pages 729-735 in R.D. Chancellor and {Falco tinnunculus rupicolus). Pages 151—162, in M.K. B.-U. Meyburg [Eds.], Raptors at risk. World Working Nicholls and R. Clarke [Eds.], Biology and conserva- Group on Birds of Prey and Owls, Hancock House, tion of small falcons. Hawk & Owl Trust, London, Blaine, MN U.S.A. U.K.

Janes, S.W. 1985. Habitat selection in raptorial birds. Pag- . 1994. A comparison of the diet of the Common es 159-187 in M.L. Cody [Ed.], Habitat selection in Kestrel Falco tinnunculus in South Alfica and Europe birds. Academic Press, New York, NY U.S.A. Bird Study 4:124—130. Johnson, D.R. 1978. The study of raptor populations. ViRANi, M. 1995. The ecology of the endangered Sokoke Univ. Press of Idaho, Moscow, ID U.S.A. Scops Owl Otus ireneae. M.S. thesis, Leicester Univ

Kasper, J.E. 1987. Ilha da Boa Vista, Cabo Verde: aspectos Leicester, U.K. historicos, socias, ecologicos e economicos; tentativa and R.T. Watson. 1998. Raptors in the east Afri- de analise. Instituto Caboverdeano do livro, Praia, can tropics and western Indian Ocean islands: state Cape Verde. of ecological knowledge and conservation status. / Leisler, B., H.W. Ley, and H. Winkler. 1989. Habitat Raptor Res. 32:28-39. behaviour and morphology of Acrocephalus warblers: Whalen, D.M., B.D. Watts, and D.W. Johnston. 2000. an integrated analysis. Ornis Scand. 20:181-186. Diet of autumn migrating Northern Saw-whet Owls on

Lopez-Jurado, L, F., J.A. Mateo, and P. Geniez. 1999. Los the eastern shore of Virginia. /. Raptor Res. 34:42-44 reptiles de la isla de Boavista (archipielago de Cabo Verde). Bol. Assoc. Herp. Esp. 10:10-13. Received 13 November 2003; accepted 29 August 2004 .

The Role of Thyroxine on the Production of Plumage in the American Kestrel {Falco Sparverius)

Michael J. Quinn, Jr.^ Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742 U.S.A.

John B. French, Jr. U.S. Geological Survey, Patuxent Wildlife Research Center, 11510 American Holly Drive, Laurel, MD 20708 U.S.A.

F.M. Anne McNabb Department of Biology, Virginia Tech, Blacksburg, VA 24061 U.S.A.

Mary Ann Ottinger Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742 U.S.A.

Key Words: American Kestrel; Falco sparverius; thyroxine, study are important secondary sexual characters for the plumage, feather, molt. American Kestrel (Wiehn 1997a, 1997b). The objectives

of this study were to: (1) investigate the roles of thyroid

In a prior study (Quinn et al. 2002) , we examined the hormones in molt in American Kestrels, and (2) deter- effects of Aroclor 1242 (a mixture of polychlorinated bi- mine the relative roles of thyroxine in plumage pigmen- phenyls [PCB]) on feather production in the American tation.

Kestrel {Falco sparverius) The development of plumage is heavily influenced by the action and timing of thyroid Methods hormones (Owens and Short 1995, Kuenzel 2003). Al- American Kestrels used in this study were 1-yr-old off- though Aroclor was shown to cause decreases in 1242 spring from a captive colony at the U.S. Geological Sur- plasma thyroxine (Quinn et al. 2002), no significant dif- vey Patuxent Wildlife Research Center (Laurel, MD). ferences were observed in feather production or appear- Pairs were randomly assigned to flight cages measuring ance between PCB and control treatments. The data pre- ca. 24 X 4 X 6 m. Seven pairs of kestrels per treatment sented here illustrate the relative roles of thyroxine on received food that was treated with either 10 ppm thy- 5' molt and plumage pigmentation in the American Kestrel. roxine (3, 3', 5, tetradiodo-L-thyroxine free acid) or 2000 propylthiouracil (6-n-propyl-2-thiouracil) a Although it is well known that molt and feather re- ppm , growth are dependent on thyroid hormones, the under- thyroid hormone blocker (Sigma Chemical Co., St. Lou- is, MO U.S.A.). Treatment levels were chosen to be non- lying mechanisms remain unclear. Experimentally-admin- lethal, but above estimated no-observed-effects levels istered thyroid hormones typically induce molt, and (May 1980, Leung et al. 1985, Lien et al. 1987, Kai et al normal schedules of molt and feather regrowth are as- 1988, Slopes 1997, al-Afaleq and Homeida 1998). Chem- sociated with changes in thyroid hormones (Kuenzel icals were mixed with rice flour, and the resulting mix- 2003). Sequence of molt also is modulated by thyroid ture was added to the kestrels’ standard diet of horse- hormones (Payne 1972). Feather loss and regrowth oc- meat (Nebraska Brand Bird-of-Prey Diet, Central curs in a regular sequence along each feather tract. Pat- Nebraska Packing, North Platte, NE U.S.A.). Rice flour terns in thyroxine-induced molts may depart from the constituted 1% of the final mixture; therefore, six pairs orderly sequence of feather replacement observed in nat- of kestrels received the control diet of horsemeat with ural molts. The melanin content and structure of bar- flour and without chemicals at 1%. Treated food was giv- bules in feathers, that would affect feather color and pat- en ca. 1 wk before egg laying began (second week of and ended when the birds finished molting in the terns, also can be altered by high levels of circulating June) fall (second week of October). Each kestrel was fed two thyroid hormones (Payne 1972). 2.0 g treated horsemeat balls daily from Monday through The timing and quality of feather loss and regrowth Friday and two untreated mice on Saturday. They were can affect many aspects of a bird’s life. Thermoregulation fasted on Sunday to help ensure hunger for the treated and flight can be significantly affected by changes in food. plumage production (Dawson et al. 2000). Feathers also We collected the outermost secondary-flight feathers communicate mate quality and age in a number of spe- from the right wing and the second rectrix from the mid- cies. The plumage colors and patterns measured in this dle on the right side of the tail from each male and female after they had regrown under treatment. Feather position was numbered according to Willoughby (1966) ^ Email address: [email protected] The width of the male black subterminal band on the

84 March 2005 Short Communications 85

second rectrix was measured at the rachis to the nearest 0.1 mm using slide calipers. We assessed color in two ways: by comparing the colors of the feathers to color chips in a Munsell soil color chart (Macbeth 1994), and by measuring feather reflectance from 230-800 nm with a reflectance spectrophotometer (PerkinElmer UV/VIS/NIR Spectrophotometer, Lambda £ 19, Norwalk, CT U.S.A.). For visual analysis, the colors £ were ranked from 1 (light) to 4 (dark) according to four _ soil color chips per color that best matched the brown ^ or gray colors analyzed (Quinn et al. 2002). When we *5 ranked females’ rectrices, we measured the first brown ^ band above the black subterminal band on the wider side C of the vane. For females’ secondaries, we ranked the area (Q in the first complete band from the tip. Color was ranked in the first available 3X10 mm area of brown right above the subterminal band on males’ rectrices and in a similar sized area of charcoal gray on the males’ secondaries. An overall score was determined by taking the mean of the tail and wing ranks, and this score was used in subsequent analyses. The same areas of color on retrices that were scored with the soil color chart were analyzed for reflectance using the reflectance spectrophotometer. Reflectance Treatment measurements were recorded from 230-800 nm at 1 nm Figure 1. Width (mm) of subterminal bands on the re- intervals. A 3 X 10 mm diameter spot on each area of color was presented flat against the aperture of the spec- trices of male American Kestrels treated with 10 ppm thy- trophotometer, with the vane perpendicular to the beam roxine or 2000 ppm propylthiouracil. Error bars are stan- of light. Data consisted of reflectance calculated as a per- dard errors of the mean. V = 7 for the thyroxine and centage of light reflected from a standard white block of propylthiouracil treatments and 6 for the control treat- vitrolite, a near-flawless diffusing surface. Reflectance ment. Means labeled as “A” are significantly different measurements were conducted at the National Institute than those labeled as “B.” of Standards and Technology, Gaithersburg, MD. The progress of molt for primaries and retrices was recorded weekly by capturing each bird and recording time differences. All other data were analyzed by two-way feathers lost and the length of growing feathers. Timing ANOVA. Data were analyzed separately by sex for sexu- of molt was measured by date of onset and total duration ally-dimorphic characters and when sex-by-treatment in- of molt. Date of molt onset is the date when the first teractions were significant. Tukey tests were used for post primary feather dropped. The duration of molt was mea- hoc pairwise comparisons. Statistical computations were sured as the interval between the onset of molt and the performed using SPSS for Windows, Version 8.0 (SPSS complete regrowth of the last rectrix. The sequence of 1998). molt was averaged within treatment groups for each primary and rectrix and compared to sequences recorded Results by Willoughby (1966). There was no overall effect of treatments on plumage Approximately 1.0 ml of blood was collected weekly color as measured by the Munsell color scores. However, from the jugular vein using a syringe rinsed with a sodi- treatments did have a significant effect on the width of um heparin solution. Each sample was centrifuged, and the subterminal bands on male retrices (Fig. P= 0.02). the plasma was collected and stored at — 70°C. Plasma 1; thyroxine was measured in duplicate samples with a dou- Subterminal bands from thyroxine-treated birds were ca. ble antibody radioimmunoassay (RIA; Wilson and Mc- 4 mm wider than those from control (P = 0.038) and Nabb 1997). We validated the RIA for hormone mea- PTU (P = 0.008) treated birds. surements on kestrel plasma by demonstrating Reflectance of feather colors did not differ significantly parallelism of the standard curve and diluted and hor- among males of different treatments in the visual range, mone-spiked samples of kestrel plasma. Sensitivity was and only marginal differences existed for males in the 12.5 |jl1 and precision, as coefficient of variation, was ultraviolet range (P = 0.07). However, there were signif- 3.1%. icant treatment differences between reflectance for fe- Data on reflectance were averaged for every 100 nm males (Fig. 2) in the visual (P = 0.004) and the ultravi- from 800-400 nm (visual range) and analyzed by multi- olet ranges (P = 0.019). Feathers from thyroxine-treated variate analysis of variance (MANOVA). Data from 399— 230 nm (UV range) were analyzed separately by two-way birds were significantly more reflective of light of wave- analysis of variance (ANOVA). Plasma-thyroxine levels lengths from 400-700 nm (400-499 nm: P < 0.05; 500- were analyzed by analysis of covariance with week of sam- 599 nm: P < 0.05; 600-699 nm: P < 0.05) and only mar- ple collection as the covariate to account for possible ginally more reflective from 700-800 nm (P = 0.057). 86 Short Communications VoL. 39, No. 1

Wavelength (nm) Control

Treatment

Figure 3. Mean (±SE) number of days in molt period of American Kestrels treated with 10 ppm thyroxine or 2000 ppm propylthiouracil. Error bars are standard errors of the mean. N = 7 for the thyroxine and propylthiouracil treatments and 6 for the control treatment Means labeled as “A” are significantly different than that labeled as “B.” Wavelength (nm)

Thyroxine The duration of molt (Fig. 3) differed significantly among the treatment groups in both males and females (P < 0.001). Birds that received thyroxine-treated food required fewer days to complete their molt than birds from control (P < 0.005) and PTU (P < 0.001) treatments. The sequence of molt from the thyroxine-dosed kestrels differed from the rest of the treatment groups only in the order of loss and replacement of the first and tenth primaries. The primaries from the thyroxine group molted in the same order as wild American Kestrels observed by Willoughby (1966). Although the sequence of molt for the retrices did not differ among treatments, slight differences were observed between all our treatment groups and Willoughby’s birds in the sequence of Wavelength (nm) molt of the last three retrices. However, the variations m Pi'opyltliioiu'acil our observed molt sequences did not deviate from the natural pattern of variability originally described by Wil-

Figure 2. Reflectance of feathers in the visual (400-800 loughby. nm) and ultraviolet (230-399 nm) ranges from female Hormone assays confirmed clearly the effects of the American Kestrels treated with 10 ppm thyroxine or 2000 thyroxine treatment on plasma thyroxine concentrations ppm propylthiouracil. N = 4 for the thyroxine treatment, in both males and females from the second to the fifth

6 for the propylthiouracil treatment, and v5 for the con- week of treatment (P< 0.0001; Fig. 4). Plasma thyroxine trol treatment. Mean reflectance from graph labeled as concentrations from PTU-treated kestrels were consis- “A” was significantly different than graph labeled as “B.” tently lower than controls; however, these differences were not significant.

Discussion

The goals of this research were to determine the relative roles of thyroxine in plumage pigmentation and molt in American Kestrels. The observed changes in March 2005 Short Communications 87

Slopes 1997). During this time, birds are reproductively unresponsive to light and, therefore, are able to devote more energy and resources to molting and plumage pro- I duction. A possible explanation of our results is that the (as onset of molt may only require a threshold level of thy-

roxine that may have been exceeded in all of the treatments. If this was true, we may have seen an effect in the

PTU-treated birds if that treatment had significantly low- ered thyroxine levels. In regard to the slight differences observed in molt that 1 2 3 4 5 sequence, Payne (1972) suggested the pattern of feather loss and regrowth may be altered in thyroxine- Weeks After Treatment induced molts. However, there is little evidence in the

current literature or in our study to support this. Se- quence of molt may be modulated more by genetic factors than hormonal ones. Eeather loss and regrowth involve an intricate interplay of environmental, nutritional, behavioral, and hormonal factors that varies among species (Berry 2003, Kuenzel

2003) . Much of what is known about feather production comes from studies of poultry and songbirds. This was

the first study to the authors’ knowledge that begins to examine the role of the endocrine system on molt and plumage pigmentation in a raptor. We found that thyroxine modulated plumage production in American Kes-

trels; however, it appeared that other unidentified factors Weeks After Treatment may have played stronger roles in this process. More stud- Figure 4. (±SE) plasma thyroxine concentrations Mean ies are needed to explore the individual roles and inter- (ng/ml) in male (A) female (B) Kestrels and American actions of the myriad of signals that are involved with treated with ppm thyroxine or ppm propylthi- 10 2000 feather loss and regrowth. ouracil. Error bars are standard errors of mean. N = 7 for the thyroxine and propylthiouracil treatments and 6 PaPEL DE Ia TiROSINA EN la PrODUCCION DEI. Plumaje en for the control treatment. Falco sparverius

Resumen.—^Aunque es sabido que el desarrollo del plu- feather pattern and reflectance in thyroxine-treated birds maje es modulado en parte por la accion de las hormo- suggest an influence of thyroxine on feather pigmenta- nas tiroideas, se sabe poco sobre el grado al cual estas tion. No such alterations were observed in the PTU-treat- hormonas controlan la perdida reemplazo de las plu- ed birds, suggesting that although thyroid hormones y mas la pigmentacion en las aves rapaces. En este estu- modulate certain aspects of molt and feather production, y dio, halcones de la especie Falco sparverius recibieron ah- other hormones may also play a role. Estradiol, testoster- mento tratado con 10 ppm de tirosina o con 2000 ppm one, and prolactin also have strong effects on feather loss de propiltiouracilo (PTU, un bloqueador de la tiroides) and regrowth (Vevers 1962, Nolan et al. 1992, Dawson diariamente desde una semana antes de que comenzara and Sharp 1998). Clearly more studies are needed to bet- la puesta de huevos hasta el final de la muda. La dura- ter understand the hormonal interactions in this com- cion la las vuelo fue significati- plex process. de muda de plumas de vamente corta en halcones que recibieron tirosina Our data suggest that thyroxine may not play as signif- mas icant a role in the American Kestrel for initiation of molt La aparicion de las plumas fue evaluada midiendo el co- as in other species. Although the onset of molt was un- lor (utilizando una carta de colores de referenda), la affected by treatments, thyroxine decreased the amount reflectancia de 230-800 nm y el ancho de la banda sub- of time required to complete a molt. Dawson et al. terminal de la cola del macho. Los halcones tratados con (2000) state that in most birds, onset of molt is most tirosina tuvieron bandas terminales significativamente heavily influenced by termination of breeding and that mas anchas. Las plumas de hembras tratadas con tirosina rate of molt is more affected by seasonal changes in day presentaron valores de reflectancia significativamente length. Longer day lengths combined with increased lev- mayores, tanto dentro del rango visual como del ultra- els of thyroxine play a stronger role in implementing re- violeta, que las hembras que recibieron PTU. fractoriness to reproduction (Wilson and Reinert 1996, [Traduccion del equipo editorial] 88 Short Communications VoL. 39, No. 1

Acknowitdgments Noian V., Jr., E.D. Ketterson, C. Ziegenfus, D.P. Cul- len, C.R. Testosterone avi- We are thankful for the guidance of Yvonne Barnes at AND Chandler. 1992. and the National Institute of Standards and Technology with an life histories: effects of experimentally elevated tes- the reflectance measurements. We are also grateful for tosterone on prebasic molt and survival in male the help and guidance of Greg Paulson and Tim Maret Dark-eyed Juncos. Condor 94:364—370. at Shippensburg University and the helpful suggestions Owens, I.P.F. and R.V. Short. 1995. Hormonal basis of Raptor Research referees. of the Journal of This work was sexual dimorphism in birds: implications for new the- funded in part by EPA Star Grant No. R-82'7400-01-0. ories of sexual selection. Trends Ecol. Evol. 10:44—47. Payne, R.B. 1972. Mechanisms and control of molt. Pages Literature Cited 103-155 in D.S. Earner and J.R. King [Eds.], Avian al-Afaleq, A.I. and A.M. Homeida. 1998. Effects of low- biology. Academic Press, New York, NY U.S.A.

doses of oestradiol, testosterone, and dihydrotestos- Quinn, M.J., Jr., J.B. French, Jr., F.M.A. McNabb, and terone on the immune response of broiler chicks. Im- M.A. Ottinger. 2002. The effects of polychlorinated munopharmacol. Immunotoxicol. 20:315—327. biphenyls (Aroclor 1242) on thyroxine, estradiol, Berry, W.D. 2003. The physiology of induced molting. molt, and plumage characteristics in the American

Poult. Sci. 82:971-980. Kestrel {Falco sparverius). Environ. Toxicol. Chem. 21’ Dawson, A., S.A. Hinsley, P.N. Ferns, R.H.C. Bonser, 1417-1422. AND L. Eggleston. 2000. Rate of molt affects feather Siopes, T. 1997. Transient hypothyroidism reinitiates egg quality: a mechanism linking current reproductive ef- laying in turkey breeder hens: termination of photo-

fort to future survival. Proc. R. Soc. Lond. 267:2093- refractoriness by propylthiouracil. Poult. Sci. 76:1176— 2098. 1782. AND PJ- Sharp. 1998. The role of prolactin in the SPSS Inc. 1998. SPSS base 8.0 for Windows user’s guide development of reproductive photorefractoriness and SPSS Inc., Chicago, IL U.S.A. postnuptial molt in the European Starling (Sturnus Vevers, H.G. 1962. The influence of the ovaries on sec-

vulgaris). Endocrinology 139:485-490. ondary sexual characters. Pages 263-289 in S. Zuch- Kai, O., H. Nagase, N. Ishikawa, M. Suzuki, T. Kakega- erman [Ed.], The ovary. Academic Press, New York, WA, AND K. Sato. 1988. Effects of propylthiouracil NY U.S.A.

(PTU) on the immunological status of the chicken. Wiehn, J. 1997a. Plumage characteristics as an indicator

Dev. Comp. Immunol. 12:145-156. of male parental quality in the American Kestrel. J. Kuenzel, W.J. 2003. Neurobiology of molt in avian spe- Avian Biol. 28:47-55.

cies. Poult. Sci. 82:981-991. . 1997b. Mate choice and reproductive success m Leung, F.C., J.E. Tayi.or, and A. Van Iderstine. 1985. the American Kestrel: a role for blood parasites? Ethol- Effects of dietary thyroid hormones on growth, plas- ogy 103:304-317.

ma T3, and T4, and growth hormone in normal and Willoughby, E.J. 1966. Wing and tail molt of the sparrow hypothyroid chickens. Gen. Comp. Endocrinol. 59:91- hawk. Auk 83:201-206. 99. Wilson, C. and F.M.A. MgNabb. 1997. Maternal thyroid

Lien, R.J., J.R. Cain, and S.L. Beasom. 1987. Effects of hormones in Japanese Quail eggs and their influence dietary and parental estrogens on bobwhite repro- on embryonic development. Gen. Comp. Endocrinol.

duction. Poult. Sci. 66:154—161. 107:153-165.

Macbeth. 1994. Munsell soil color chart. Macbeth Divi- Wilson, F.E. and B.D. Reinert. 1996. The timing of thy- sion of Kollmorgen Instrument Corporation, New roid-dependent programming in seasonally breeding Windsor, NY U.S.A. male American Tree Sparrows {Spizella arbored). Gen May, J.D. 1980. Effect of dietary thyroid hormone on Comp. Endocrinol. 103:82—92.

growth and feed efficiency of broilers. Poult. Sci. 59: 888-892. Received 27 June 2003; accepted 6 October 2004 ,

Observations of Nesting Gray-headed Kites {Leptodon cayanensis) IN Southeastern Brazil

Eduardo Pio Mendes de Carvalho Filho,^ Gustavo Diniz Mendes de Carvalho, AND Carlos Eduardo Alencar Carvai.ho S.O.S. Falconiformes Research Center for the Conservation of Neotropical Raptors, Rua Odilon Braga, n" 1370 Bairro Mangabeiras—Belo Horizonte, Minas Gerais, Brazil

Key Words: Gray-headed Kite, Leptodon cayanensis; e^s; made using 10 X binoculars at distances of 15 m. An ob- nest structure, nestling, nesting biology, southeastern Brazil. servation blind was constructed in a tree up slope of each nest. We measured nest dimensions with a tape measure, and nest heights using a direct line above the ground The Gray-headed Kite {Leptodon cayanensis) occurs in We measured eggs with calipers, to the nearest 0.1 mm lowland tropical forests from the Amazon region, west to During 130 hr of observation, we noted adult behavior Ecuador, north to the Guianas and Trinidad, and south- at and near nests, and recorded prey deliveries. Nestlings ern Tamaulipas and Oaxaca, Mexico (del Hoyo et. al were marked with aluminum bands. We could not distm- 1994). This raptor is characterized by a gray head, black- guisb between the adults on most of the occasions when ish back, white chest and legs. It ranges in length from they visited the nests. 46-54 cm, and has a mass between 416-643 g (Brown and Amadon 1989, Thorstrom 1997). Current knowledge Resui.ts about this species is mostly anecdotal, with the exception We located two nests in 1999 and one in 2001 in two of a description of nests and behavior in Guatemala different territories. (Thorstrom 1997). We studied this species in southeast- Nest 1. On 12 September 1999, we observed a Gray- ern Brazil, where in Brazil, Gray-headed Kites were prob- headed Kite building a nest 15 m up in a Copaiba tree ably restricted to the Amazon basin (Sick 1997). In this {Copaifera langsdorffii) that was 16.5 m tall and 155 cm in paper, we present new information on the eggs, nests, diameter breast height (DBH). The nest was 52 m from nesting behavior, and diet of the Gray-headed Kite. an occupied Rufous-thighed Hawk {Accipiter erythrone- Study Area and Methods mius) nest. The habitat around this nest site consisted of Cerrado complex. On our next visit (29 September) an We collected data from July 1999-September 2001 in , adult kite was observed incubating. climbed the nest two different areas and cover types. The first study site We (19°2TS, 44°12'W) was in the municipality of Sete La- tree and observed two eggs. The eggs had many conspic- goas, ca. 60 km north of Belo Horizonte. The mean an- uous dark-brown spots, with a greater concentration of nual rainfall is 1328.7 mm, and the mean annual tem- spotting near the base and fading toward the narrow end perature ranges from 15.6-28.2°C. The altitude of the The eggs measured 50.7 X 40.8 mm and 52.1 X 40.7 mm site varies between 700-900 m. This area is characterized (Fig. 1). The nest was made of small-diameter twigs and by pasture containing some small forest fragments. Al- measured 39 X 39 cm across, and was 13.9 cm in depth. most all the forest habitat of this region has been con- The nest cup measured 21 X 22 cm and was 7.5 cm deep verted to pastures. The second site (20°02'S, 43°59'W) first It covered was located in Belo Horizonte, in a protected area called On 17 October the young hatched. was APE (environmental protection area), located in the Bar- with fluffy white down and had a yellow cere and tarsi, reiro district, which belongs to the sanitation company of black beak, and a black supraocular stripe. On 14 Novem- Minas Gerais (COPASA-MG). The mean annual rainfall ber 1999, nearly one month after hatching, the nestling’s is 1300 mm, and the mean annual temperature ranges body was covered with white downy feathers and its wing from 18—24°C. The altitude of the site varies between and tail feathers were starting to emerge from the blood 850-950 m. The cover type at this site consists of a Cer- sheaths. The cere and feet were brighter yellow than rado complex and riparian forests. The composition of a when the chick was younger; the young was banded dur- Cerrado biome consists of species such as cagaita tree ing this visit. From the tree blind, we observed adult kites {Eugenia dysenterica pequi tree ( Caryocar brasiliense) ipe ) , tree {Tabebuia ochracea), macaw palm {Acrocomia aculeate), delivering small, dark-colored snakes {N = 6 snakes) m and araticum tree {Annona crassiflora; Lins and Mendon- their talons to feed the nestling. The nestling swallowed ca 2000) the snakes whole, making identification difficult. Total In both areas, we searched for all nesting raptors, es- observation time at this nest was 56 hr. In this nest, 2 pecially, in forested areas. We observed the three Gray- young hatched, but only one fledged. headed Kite nests that we found as frequently as possible Nest 2. On 14 October 1999, we discovered a second from July 1999-September 2001. Observations were nest, with an adult incubating. This nest was composed of small sticks, 16.5 m above ground in a 17.5 m high in ^ Email address: [email protected] a Brazilian cherry {Peltogyne confertiflora) 140 cm in DBH.

89 90 Short Communications VoL. 39, No. 1

Figure 1. Egg and nest of Gray-headed Kites, in Minas Gerais, Brazil. Photo by Gustavo Diniz M. Carvalho.

The nest was 79 m from an occupied Bicolored Hawk cere and feet were dark yellow. This nesding was quite {Accipiter bicolor) nest. On 19 October, we visited the nest aggressive and attacked us with its feet when we banded and observed two heavily brown-spotted eggs similar to it (Fig. 2). On this date, we observed three dark-colored those at the first nest. We could not reach the nest, and snakes delivered to the nesding by an adult. Based on therefore, no measurements were taken. On 4 Novem- casual observations, we believe that this pair commonly ber, the pair was still incubating when we visited this site. hunted in the open areas of the Cerrado. The total time On 15 November we made another visit to this nest, and of nest observation was 41 hr. found the nest empty and abandoned. The cause of fail- Discussion ure may have been a severe rainstorm that moved through the area several days earlier. Total observation At the three Gray-headed Kite nests that we observed time at this nest was 20 hr. in southeastern Brazil, the breeding season began in Sep- Nest 3. On 2 October 2001, we observed a pair of kites tember with nest construction, incubation began by early on a nest in the same crotch of the same tree where the to mid October, and young fledged in late November and first nest was located on 12 September 1999 (nest 1). The December. Each of three nests held a two-egg clutch. A nest was 63 m from an occupied Rufous-thighed Hawk one-egg clutch was reported by Thorstrom (1997) in nest. The nest was constructed with new sticks and mea- Guatemala, and two and three eggs were reported for two sured 40 X 40 cm in diameter and 13.8 cm in depth. The nests of this species by del Hoyo et al. (1994). However, nest cup was 22 X 21 cm and 8 cm deep. The nest held the three-egg clutch reported by del Hoyo et al. (1994) two heavily brown-spotted eggs, which measured 52.0 X apparendy was erroneous. The original data slips for 40.7 mm and 51.1 X 40.8 mm. We returned on 2 Novem- these three eggs were obtained and examined by D. Whi- ber, when we found two small nestlings, one of them vis- tacre (pers. comm.) and these clearly describe three sin- ibly larger than its sibling. They were brown and covered gle-egg clutches. Gray-headed Kites appear to lay a one- by white down, and their feet and cere were dark yellow to two-egg clutch. Our eggs averaged 51.5 X 40.8 mm, with a black supraocular stripe. On 25 November, we slighdy smaller than the 54.8 X 42.1 mm egg reported again visited the nest and found only one nesding. Its from Guatemala (Thorstrom 1997). The smaller egg sizes head and back were a mixture of dark gray and black we found in Brazil may be related to the cost of laying a plumage and its chest was white, striped with black. Its two-egg versus a one-egg clutch in Guatemala. March 2005 Short Communications 91

Figure 2. The fledgling Gray-headed Kite at nest 3 in (Belo Horizonte) Sete Lagoas-MG, Brazil. Photo by Eduardo Pio Carvalho.

All nests were composed of small dry sticks, and were buffy-headed marmosets {Callithrix Jlaviceps', Ferrari flimsily constructed in the crotch near the end of a small- 1990). diameter branch. The three Brazilian nests, averaged We observed that all three nests were located near to 39.5 X 39.5 cm and the nest cups averaged 21.5 X 22.5 occupied Accipiter nests. Thorstrom et al. (in press) also cm and with a depth of 7.8 cm, similar in size to the nest observed one nest of the Gray-headed Kite 50 m from an described in Guatemala (Thorstrom 1997). occupied Bicolored Hawk {Accipiter bicolor) nest in Gua- Young Gray-headed Kites fledged with dark pupils, temala. dark gray and black feathers on the head and back, a The Gray-headed Kite is an uncommon species in the white chest with vertical dark-brown streaks, white tarsal Sete Lagoas area, perhaps due to deforestation. Conser- feathering, and dark-yellow cere and feet. Also, there may vation of the remaining forest fragments is likely impor- be vciriations of the immature plumage (Foster 1971) that tant for preserving this and other species dependent on we are not able to describe. these woodlands for nesting. Gray-headed Kites are reported to feed on many dif- OBSERVACIONES SOBRE la NlDinCACION DE Leptodon caya- ferent insects, with a fondness for wasp larvae (Hyme- NENSIS EN EL SUDESTE DE BRAZIL noptera; Haverschmidt 1962, Brown and Amadon 1989), and stomach contents have included remnants of a frog Resumen.—Estudiamos individuos de la especie Leptodon and a bird’s egg (Haverschmidt 1962). The only prey cayanensis que se encontraban nidificando entre julio de items we observed Gray-headed Kites delivering to nests 1999 y septiembre de 2001. Las observaciones se reali- were nine snakes. Based on the strong odor of two cap- zaron en dos sitios con diferentes tipos de cobertura: una tured adults, Thorstrom (1997) speculated that these pradera con parches remanentes de bosque y un bosque kites may feed upon snakes. There has also been a report ribereno. La construccion de los nidos comenzo en sep- of a feeding association between Gray-headed Kites and tiembre, la incubacion ocurrio en septiembre y octubre. —

92 Short Communications VoL. 39, No. 1

y los polluelos salieron de los nidos entre noviembre y DEL Hoyo, J., A. Elliott, and J. Sargatal (Eds.). 1994 diciembre. Los nidos fueron de construccion endeble y Handbook of the birds of the world. Vol. 2. New constituidos por ramas secas y se situaron en las bifur- World Vultures to Guineafowl. Lynx Edicions, Barce- caciones de las ramas de arboles a una altura promedio lona, Spain. = de 15 m sobre el suelo {N 3). Las dimensiones pro- Eerguson-Lee, J, and D.A. Christie. 2001. Raptors of the medio de los nidos fueron 39,5 X 39.5 cm y 13,9 cm de world. Houghton Mifflin Company, Boston, MA profundidad exterior, con una copa de 21,5 X 22.5 cm y U.S.A. 7 8 cm de profundidad. El tamano modal de la nidada Eerrari, S.E. 1990. A foraging association between two = fue dos {N 3 nidos) . Los huevos presentaron manchas kite species {Ictinia plumbea and Leptodon cayanensis) de color cafe con marcas mas fuertes en la base {N = 6 and buffy-headed marmosets {Callithrix flaviceps) in huevos) y tuvieron un tamano promedio de 51.5 X 40.8 southeastern Brazil. Condor 92:781—783. mm (N = 4). Los polluelos eclosionaron de forma asin- Eoster, M.S. 1971. Plumage and behavior of a juvenile cronica. En total, de tres intentos de nidificacion, dos Gray-headed Kite. Auk 88:163—166. polluelos emplumaron exitosamente, lo que representa Haverschmidt, F. 1962. Notes on the feeding habits and un exito de nidificacion del 66.6%. Todas las presas lle- food of some hawks in Surinam. Condor 64:154-158. vadas a los polluelos en el nido fueron serpientes (N = Lins, L.V. and M.P. Mendonca. 2000. Lista Vermelha das 9). especies ameagadas de extin^ao da flora de Minas [Traduccion del equipo editorial] Gerais. Publicafoes avulsas da Fundagao Biodiversitas e Funda^ao Zoo-Botanica de Belo Horizonte, Belo Acknowledgments Horizonte, Brazil. We thank Russell Thorstrom for an earlier review of Sick, H. 1997. Ornitologia Brasileira. Editora Nova Fron- this manuscript, Silva e Silva for supplying ref- Robson teira, Rio de Janeiro, Brazil. erence material and literature, Jane Elce Scheid Ramos Thorstrom, R.K. 1997. A description of nests and be- for help in the preparation of the manuscript, INMET havior of the Gray-headed Kite. Wilson Bull. 109:173- National Meteorology Institute (5° Meteorology District) 177. for providing us with climatic data on the first studied

, D.F. area, and Dave Whitacre for his information, references, Whitacre, J. Lopez, and G. Lopez. In press and review. Gray-headed Kite {Leptodon cayanensis) . /n D. Whitacre [Ed.], Raptors of the Maya Forest: ecology of a trop- LriERATURE Cited ical forest raptor community. Cornell Univ. Press, Ith-

Brown, L. and D. Amadon. 1989. Eagles, hawks, and fal- aca, NY U.S.A. cons of the world. The Wellfleet Press, Seacaucus, NJ U.S.A. Received 15 July 2003; accepted 19 September 2004

Cooperative Nesting by a Trio of Booted Eagles {Hieraaetus pennatus)

Jose E. Martinez,^ Cari.os GonzAlez, and Jose F. Calvo Departamento de Ecologia e Hidrologia, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain

Key Words: Booted Eagle; Hieraaetus pennatus; coopera- that this was a frequent phenomenon in well-studied spe- tive breeding, polygamy; polygyny; trio. cies and that the mating system was probably not determined in many other species because of the difficulty in

Although monogamy is the most common mating sys- making appropriate observations and given the fact that tem among raptors, alternative systems like polygyny, many raptors have not been well studied (Kimball et al. polyandry, and cooperative breeding have been recorded 2003). Cooperative breeding has been observed among m several species (Newton 1979, Korpimaki 1988, Stacey 3% of bird species, including at least 42 diurnal raptors and Koening 1990). A recent review on the topic showed (Brown 1987, Kimball et al. 2003). Here, we report a case of cooperative nesting by a trio in an intensively-monitored breeding population (21-29 ^ Email address: [email protected] pairs) of Booted Eagles {Hieraaetus pennatus) in south- March 2005 Short Communications 93 eastern Spain. Our observations were made in 2001 in a tree most of the time. The helper female (F2) was ob- mountainous area of the Region of Murcia (southeastern served only twice with El in the nest. When the male

Spain), characterized by large tracts of pine forests {Pinus approached the nest with prey, it emitted food-begging halepensis) interspersed with smaller clearings of cultivat- calls, which prompted calling from both females. F2 was ed lands and scrubland. The Booted Eagle is a medium- never observed delivering prey to nest. On one occasion sized, territorial raptor that nests on trees and rocky cliffs both females attacked a Common Raven {Corvus corax). m forested areas of the Palearctic and sub-Saharan re- The pair and the helper female successfully reared one gions (del Hoyo et al. 1994). This species is considered young, who flew for the first time between 5-10 July 2001 a monogamous raptor (Newton 1979, Cramp and Sim- mons 1980) and to our knowledge no instances of trios Discussion at nests have been reported. The above described case of apparent polygyny can be In the Iberian Peninsula, Booted Eagles are generally considered cooperative breeding because all the mem- summer residents, arriving from their wintering grounds bers of the breeding unit contributed to the care of a in late March and early April. In our study area, nest single nest (Kimball et al. 2003). We suggest that coop- building or reconstruction occurs soon after the eagles erative breeding in the Booted Eagle is uncommon be- arrive and their mean laying date is 24 April. cause of the lack of reports in the scientific literature. Nevertheless, we must be cautious with this affirmation Observations due to the difficulty in observing this kind of behavior, In 2001, during the pre-laying period, a polygynous especially for a species with poorly known breeding bi- trio was observed in one territory on the study area. The ology, as is the case of the Booted Eagle (Veiga and Vin- same territory was monitored in the previous year related uela 1994, Suarez et al. 2000). to other research. This study in 2000 involved 195 hr of The presence of helpers at raptor nests has been as- nest observations that allowed us to photograph and in- sociated with many factors, including productive habitats dividually identify the pair composed of a pale-morph with abundant food supply (Van Kleef and Bustamante male (Ml) and a dark-morph female (El). This female 1999), low prey densities (Doyle 1996), biased sex ratio was trapped and marked with a radiotransmitter mount- in adults (Oring 1986, Arroyo and Garza 1986), the reed with a backpack harness. She laid two eggs and the duced availability of suitable sites for reproduction (He- pair reared two young successfully. redia and Donazar 1990, Bertran and Margalida 2002), In 2001, when the trio was recorded, we observed the saturation of breeding territories (Heredia and Donazar nest for 46 hr. The male who occupied this nest was the 1990), potential benefits of group living (Garcelon et al. same male observed the previous year (Ml) based on 1995, Kimball et al. 2003) and benefits to yearlings that distinctive features of its plumage (blond head and neck, gain breeding experience (Zuberogoitia et al. 2003). The and white breast with numerous brown streaks) . The pre- Booted Eagle is a philopatric species (Cramp and Sim- vious year’s female (El) was identified because of the mons 1980), thus a possible explanation is that the help- transmitter. The third bird in the territory was a pale er was an individual born in the study area some years morph individual identified as an adult (the adult plum- ago and returned to its natal area for the first time. age is acquired at the third calendar year; Eorsman 1999) Whether the helper was recruited by the adults to assist female (F2) due to its size and behavior. No copulations with the breeding effort or was a previous offspring of were observed between Ml and either female. Also, dur- the pair was unknown. Based on our limited observa- ing the pre-laying period, no aggressive interactions be- tions, it was unclear which factors may have led to this tween the three individuals were observed. Instead, all cooperative breeding event. We encourage other observ- three eagles added material to refurbish the nest, al- ers working on Booted Eagles to make an effort to rec- though the bulk of this task was done by Ml (20%) and ognize individual breeders and that researchers should FI (70%; N = 10 deliveries of nest material). be aware of the possibility of cooperative breeding in this When the nest was checked on 29 April it was defend- species. ed by the adults (Ml and FI), and contained two eggs. Both females were observed to incubate the eggs, al- Reproduccion Cooperativa por UN Trio en Hieraaetus = though FI spent more time (93%; N 540 min) than PENNATUS the accompanying female We also observed the relief of El by F2 from the incubation on three occasions, Resumen.—En esta comunicacion se describe un caso de which occurred when the former left the nest to partic- reproduccion cooperativa por un trio poliginico de Hi- ipate in territorial defense, to hunt, or apparentiy to take eraaetus pennatus en una zona forestal del sureste de Es- a rest. In contrast, while El incubated, F2 perched on a pafia. El trio, observado en 2001, estaba compuesto por nearby tree. Although F2 brought greenery to the nest, un macho de fase clara, una hembra consorte de fase it was only El who situated the greenery in the nest. oscura, y una hembra acompanante de fase clara. No se During the nestling period, the two hatched young observaron copulas. Ambas hembras colaboraron en las were only fed by FI, while F2 stood perched on a nearby tareas de mantenimiento, incubacion y defensa del nido 94 Short Communications VoL. 39, No. 1

Sin embargo, la hembra consorte contribuyo mucho mas polyandrous trios in an endangered population of en las actividades reproductivas que la hembra acompah- Lammergeiers Gypaetus barbatus in northern Spain. ante; esta ultima no fue nunca observada trayendo presas Biol. Conserv. 53:163—171. al nido o cebando a los polios con el alimento aportado Kimball, R.T., P.G. Parker, and J.C. Bednarz. 2003. The por el macho. occurrence and evolution of cooperative breeding [Traduccion de los autores] among the diurnal raptors (Accipitridae and Falcon- idae). Auk 120:717-729. Acknowledgments Korpimaki, E. 1988. Factors promoting polygyny in Eu- We are indebted to Gines Gomez and Martina Carrete ropean birds of prey—a hypothesis. Oecologia77:278- for field assistance. We also thank Beatriz Arroyo, Javier 285. Balbontin, Jim Bednarz, and one anonymous referee for Newton, I. 1979. Population ecology of raptors. T. & A.D. helpful comments on the manuscript. Poyser, London, U.K. Literature Cited Oring, L.W. 1986. Avian polyandry. Pages 309-351 mR.F Johnston [Ed.], Current ornithology. Plenum Press, Arroyo, B. and V. Garza. 1986. Estudio sobre la situacion New York, NY U.S.A. del aguila real Aquila chrysdetos en el sistema central. Stagey, P.B. and W.D. Koening (Eds.). 1990. Cooperative Bol. Ecol. 30:93—104. Est. Cent. breeding in birds: long-term studies of ecology and Bertran, and a. Margalida. 2002. Social organization J. behavior. Cambridge University Press, Cambridge,

of a trio of Bearded Vultures Gypaetus barbatus) : sex- ( U.K. ual roles. Res. 36:66-69. and parental J. Raptor Suarez, S., J. BalbontIn, and M. Ferrer. 2000. Nesting Brown, 1987. Helping and communal breeding in J.L. habitat selection by Booted Eagles Hieraaetus pennatus birds. Princeton Univ. Press, Princeton, NJ U.S.A. and implications for management. / Appl. Ecol. 37 Cramp, S. and K.E.L. Simmons. 1980. The birds of the 215-223. western Palearctic. Vol. 2. Oxford Univ. Press, Oxford, Van Kleef, H. and Bustamante. 1999. First recorded U.K. J. polygynous mating in the Red Kite {Milvus milvus) . J DEL Hoyo, A. Elliott, and Sargatai.. 1994. Hand- J., J. Raptor Res. 33:254-257. book of the birds of the world. Vol. 2. Lynx Edicions, Veiga, J.P. and j. Vinueia. 1994. Booted Eagle Hieraaetus Barcelona, Spain. pennatus. Pages 182-183 in G.M. Tucker and M.F. Doyi.e, F.I. 1996. Bigamy in Red-tailed Hawks in south- Heath [Eds.], Birds in Europe: their conservation sta- western Yukon. / Raptor Res. 30:38-40. tus. BirdLife International, Cambridge, U.K. Forsman, D. 1999. The raptors of Europe and the Middle ZuBEROGOiTiA, I., J.A. MartInez, A. Azkona, A. Iraeta, I. East: a handbook of field identification. T. & A.D. Poy- Castillo, R. Alonso, and S. Hidai.go. 2003. Two cas- ser, London, U.K. es of cooperative breeding in Eurasian Hobbies. Garcelon, D.K., G.L. Slater, C.R. Danilson, and R.C. / Raptor Res. 37:342-344, Helm. 1995. Cooperative nesting by a trio of Bald Ea- gles./. Raptor Res. 29:210-213. Heredia, R. and J.A. Donazar. 1990. High frequency of Received 6 October 2003; accepted 27 July 2004

Timing and Abundance of Migrant Raptors on Bonaire, Netherlands Antilles

Vincent Nijman,’ Tineke G. Prins, and J.H. (Hans) Reuter Institute for Biodiversity and Ecosy.stem Dynamics, Zoological Museum, University of Amsterdam, RO. Box 94766, 1090 GT Amsterdam, Netherlands

Key Words: American Kestrel; Falco sparverius; Swallow- The island of Bonaire (12°10'N, 68°18'W) in the south tailed Kite; Elanoides forficatus; Yellow-headed Caracara; Caribbean Sea, 87 km north of Venezuela, is the eastern- Milvago chimachiraa; migration, Caribbean. most island of the Netherlands Antilles. Bonaire occupies

a land surface of ca. 272 km^, its climate is arid, and the

island is largely covered in xerophytic and thorny bush

^ Email address: [email protected] and sparse woodland. Some 181 species of birds have , ,

March 2005 Short Communications 95

Table 1. Records per month of migrant raptors in Bonaire, Netherlands Antilles. The migration peaks twice a year in February and October-November.

Species J F M A M J J A S O N D Pandionidae

Osprey {Pandion haliaetus) 7 7 2 5 9 5 6 3 11 12 15 5

Accipitridae

Swallow-tailed Kite {Elanoides 1

forjicatus)

Falconidae

Yellow-headed Caracara {Mil- 1 vago chimachima)

American Kestrel {Falco spar- 1 1 1 2 1 1 verius)

Merlin {Falco columbarius) 9 6 7 6 1 2 1 8 14 4

Peregrine Falcon {Falcon pere- 1 9 7 4 1 1 10 10 5 grinus) Total 17 23 17 16 10 6 10 4 13 30 40 16

been listed for Bonaire (Voous 1983). Although the is- them for further analysis. We define Bonaire as the island of the islet Klein Bonaire, not land is ornithologically relatively well explored, the num- Bonaire and of but we do include Isla las Aves situated ca. 60 km to the east. Given ber of new migrants recorded on the island is still in- that for many of the migrants arriving in the Netherlands creasing (e.g., Prins and Debrot 1996). Antilles we have no data on their specific breeding lo- Two species of raptors breed on the island, and an calities, following Voous (1983) we define migrant in its additional three species are regular nonbreeding visitors broadest sense and include all species that do not have (Voous 1982, 1983, 1985). Resident raptors have been a resident breeding population on Bonaire. We used x^- studied infrequently. The migrants have not been sub- tests to evaluate differences in the temporal distribution jected to any systematic observations (Voous 1957, 1982), of records by comparing monthly totals. Means are re-

nor is there a monitoring scheme in place. As such, Bon- ported ± 1 SD and significance is assumed when P < 0.05 two-tailed test. aire is typical for the region for which Zalles and Bildstein in a (2000) commented “With few watch-sites, movements of Results raptors in (the Caribbean) are decidedly less well understood than they are farther north in the Western Hemi- We compiled 202 records for six species of migrants sphere. As a result, (the region) ranks as the least studied on Bonaire (Table 1). The mean number of records was region in the world in this regard.” Furthermore, spatial 16.8 (±10.2) per mo or 33.7 records (±36.0) per species and temporal variation in the abundance of migrant rap- On average, 3.3 (±1.0) species of migrant raptor per mo tors in the tropics has been rarely quantified (Thiollay are present on the island, ranging from 2-5. The records 1978, Nijman 2001), largely because few monitoring pro- were not equally distributed over the year, and most mi- = grams are in place. We compiled information on the avi- grants were observed during the boreal winter (x^

fauna of Bonaire. Our aim was to provide details on the 67.7, df = 1, P < 0.001; Table 1). If we expected a uni- species composition of migrant raptors on Bonaire and form temporal distribution, each of the months of Feb- to analyze their timing and abundance on the island. ruary, October, and November had significantly more re-

cords than the other months combined (all x^ > ^-5, df Methods = 1, P < 0.01). Conversely, each of the months May- Data on the occurrence of raptors in the Netherlands August have significantly fewer records than the other Antilles were compiled from: (1) the collections of the months combined (all x^ > 4.2, df = 1, P < 0.05). Zoological Museum Amsterdam (ZMA) and Naturalis More than 40% of the records refer to the Osprey Leiden (RMNH); (2) records from the archives of the (Pandion haliaetus). The three least common species late K.H. Voous and the late Brother Candius van der (Swallow-tailed Kite \Elanoides forficatus] Yellow-headed Linden (both stored in the ZMA) of whom the latter was , Caracara [Milvago chimachima] and American Kestrel resident on Bonaire from 1967-95; and (3) data solicited [Falco sparverius] make up only of the total sample from ornithologists and observers on the island. Tem- ) 4% poral distribution of the occurrence of migrant raptors The Osprey was the only nonbreeding raptor recorded was very similar in these three data sets, so we pooled in all months, although three records of the Merlin {Falco 96 Short Communications VoL. 39, No. 1

columbarius) in June and July suggested that a small num- little overwintering, but with an even less conspicuous ber of these migrants may have remained on the island spring migration. during the boreal summer. Most migrant raptors arriving on Bonaire breed in

northern latitudes, although a small number (i.e., Yellow- Discussion headed Caracara and, most likely, Swallow-tailed Kite;

Species Composition. We documented six species of Mlodinow 2004) originate from mainland South America migrant raptors on Bonaire, three of which were not in- (Venezuela, Colombia). Few data are available on move- of raptors in at least cluded in Voous’ (1983) list of birds for the island. We ments northern South America, but documented seven records of American Kestrel from all some are partly migratory (ffrench 1973; Ferguson-Lees Christie species, the is seasons dating as far back as 1948. The species is com- and 2001). One American Kestrel mon in the region and probably was a regular visitor to a breeding resident on Aruba and Curasao, where its Bonaire, although Voous (1957, 1983) was reluctant to main breeding season is November-February (Voous accept any records of the species. Records of the other 1957, 1983). The few records we compiled from Bonaire two species were more recent, the Yellow-headed Cara- were from throughout the year, but may well have been cara in December 1996, and the Swallow-tailed Kite in either first-year birds dispersing from these nearby is- April 2002 (Mlodinow 2004). The former occurs lands, or alternatively, birds from northern regions. throughout northern South America (Ferguson-Lees and Systematic studies of raptor migration on Caribbean islands are rare, and to other parts of the Christie 2001). In the Netherlands Antilles it previously compared has been recorded on Curasao only (January 1952; Northern Hemisphere little is known about the species Voous 1983). The Swallow-tailed Kite has a disjunct dis- composition and timing of migrants in the region (Zalles tribution and breeds in the southern United States (now and Bildstein 2000). Our data set was comprised of rec- mainly Florida and adjacent states) and from southern ords obtained opportunistically, and includes the island Mexico south to Argentina (Ferguson-Lees and Christie of Bonaire only. Extending our analysis to other islands 2001). Kites from northern and central America migrate in the south Caribbean islands and to mainland areas m (including southwards during the boreal winter, whereas little is northern South America the Paraguana Pen- known about movements of populations in northern insula) may be a promising avenue along which to pro- South America. Recentiy, the species was recorded on ceed with further research. Aruba (March 2003; Mlodinow 2004), suggesting that the sighting on Bonaire might not be as unusual as previously Temporada de Estancia y Abundancia de Ayes Rapaces thought. In addition to these species, observations of a EN Bonaire, Antillas Holandesas Northern Harrier {Circus cyaneus) on Curasao (October- Resumen.— Se colectaron 202 registros de seis especies November 1997) suggested that this northern migrant de aves rapaces de la isla de Bonaire, Antillas Holandesas, also can be expected to pass through Bonaire (B. de Boer incluyendo tres especies reportadas nuevamente en la pers. comm.). isla {Elanoides forficatus, Milvago chimachima y Falco sparv- All of the migrants from Bonaire have been recorded erius). Basandonos en estos datos discutimos la tempor- on the other islands in the Netherlands Antilles, and one, ada de estancia y la abundancia de rapaces migratorias the American Kestrel, breeds on Aruba and Curasao en la isla. La abundancia maxima de migrantes tiene lu- (Voous 1983). Two of the species, the Osprey and the gar dos veces al aho durante febrero y marzo (20% del Peregrine Falcon, are known from the Los Roques Is- total anual) y durante octubre y noviembre (35%), sim- lands east of Bonaire (Zalles and Bildstein 2000). ilar al patron observado en las cercanfas de Venezuela Timing of Migrant Raptors. Several distinct phases can Se identificaron tres grupos de aves rapaces migratorias. be recognized with respect to the timing of northern mi- El primero, migrantes de Norte America que pasan por grant raptors on Bonaire. The first phase from Septem- Bonaire hasta llegar a las planicies de Sudamerica; el se- ber-November was characterized by the arrival and pas- gundo, especies que se dispersan por Sudamerica hasta sage of a relatively large number of migrants, presumably llegar a Bonaire; y el tercero, residentes que se alimentan mostly from North America, en route to mainland South cerca de las islas y que ocasionalmente se registran en America. In December and January, the number of rec- Bonaire. ords was considerably lower and these, in part, likely rep- [Traduccion de los autores] resented birds that over-winter on the island. The second, albeit smaller, peak from February-March probably com- Acknowiudgments prised birds on return migration to their breeding We would like to thank the large number of observers grounds. Finally, a small number of individuals remained that over the years have submitted their records, includ- on the island in boreal summer from April-August. A ing C. Beachell, B. de Boer, M. Flikweert, G. van Hoorn, similar temporal pattern has been observed in migrant J.C. Ligon, and S. Mlodinow. Financial support was re- passerine birds in xerophytic habitats on the Paraguana ceived from the Van der Hucht Fund. K.L. Bildstein, R. Peninsula, Venezuela, 150 km west of Bonaire (Bosque Yosef, and G.S. Kaltenecker commented on the manu- and Lentino 1987), that is a conspicuous fall migration. script. F.R. Schram assisted with editing our English, and 1

March 2005 Short Communications 97

E. van der Vorst Roncero translated the abstract into rique occidentale: adaptations ecologiques aux fluc- Spanish. tuations de production des ecosysteraes. Terre Vie 32 89-133. Literature Cited Voous, K.H. 1957. The birds of Aruba, Curasao, and Bo-

Bosque, C. and M. Lentino. 1987. The passage of North naire. Stud. Fauna Curasao other Canbb. Isl. 29:1—260 migratory land birds xerophitic American through . 1982. Straggling to islands—South American habitats on the western coast of Venezuela. Biotrop. 19: birds in the islands of Aruba, Curagao, and Bonaire, 267-273. South Caribbean. J. Yamashina Inst. Ornithol. 14:171- Ferguson-Lees, J. and D.A. Christie. 2001. Raptors of 178. the world. Christopher Helm, London, U.K. . 1983. Birds of the Netherlands Antilles. De Wal- FFRENCH, R. 1973. guide to the birds of Trinidad and A burg Press, Utrecht, Netherlands. Tobago. Livingstone Publishing Company, Wynne- . 198.5. Additions to the avifauna of Aruba, Cura- wood, OK U.S.A. sao and Bonaire, South Caribbean. Ornithol. Monogr. Mlodinow, S.G, 2004. First records of Little Egret, 36:247-254. Green-winged Teal, Swallow-tailed Kite, Tennessee Zatles, J.I. and K.L. Bildstein (Eds.). 2000. Raptor Warbler, and Red-breasted Blackbird from Aruba. N. watch: a global directory of raptor migration sites Am. Birds 57 '.BBd-B&l. BirdLife Conservation Series 9. BirdLife Internation- Nijman, V. 2001. Spatial and temporal variation in mi- al, Cambridge, U.K. and Hawk Mountain Sanctuary, grant raptors on Java, Indonesia. Emu 101:259-263. Kempton, PA U.S.A. Prins, T.G. and A.O. Debrot. 1996. First record of the Canada Warbler for Bonaire, Netherlands Antilles.

Canbb.J Sci. 32:248-249. Received 8 January 2004; accepted 3 June 2004 Thiollay, J.-M. 1978. Les migrations des rapaces en Af- Associate Editor: James R. Belthoff

The Relationship of Foraging Habitat to the Diet of Barn Owls ( Tyto alba) FROM Central Chile

Sabine Begall^ Department of General Zoology, Faculty of Biology and Geography, University of Duisburg-Essen, D-431 7 Essen, Germany

Key Words: Barn Owl; Tyto alba; diet, Chile, feeding ecology; (Schamberger and Fulk 1974, Fulk 1976, Jaksic et al. anthropogenic disturbance. 1993b), the Chinchilla National Reserve (Jaksic et al 1992), or the Atacama De.sert (Jaksic et al. 1999). Dis- habitats activities as Several studies on the diet of the Barn Owl ( Tyto alba) turbances of hunting by human such related to broader investigations of predator-prey rela- agriculture or pollution may differentially affect the oc- tionships have been conducted in Chile, most of which currence or abundance of small mammals, and thus, the involved data collected in the semi-arid north-central diet of the Barn Owl.

zone of this country (e.g., Schamberger and Fulk 1974, In this study, I examine the diet of Barn Owls occu-

Jaksic et al. 1992, 1993b). The majority of these studies pying two ecologically-dissimilar study areas. Although dealt with predator-prey interactions, and little attention both sites are affected by humans, their extent of disturbance differs. study site (El Alamo) located in the was paid to human influences on the Barn Owl’s diet One ,

(e.g., Schlatter et al. 1980, Simeone 1995). Indeed, most south of central Chile, consisted mainly of meadows and of these studies were conducted in areas of reduced hu- was only slightly influenced by human settlement. In con- man activities such as the Fray Jorge National Park trast, the second habitat (Los Maitenes) appeared to be noticeably polluted by the copper-processing industry as indicated by substantially reduced vegetative cover. Fur-

^ Email: [email protected] thermore, the polluted habitat lies within the geograph- .

98 Short Communications VoL. 39, No. 1

ical range of previous diet studies (Jaksic and Yanez 1979, Resuits

Herrera and Jaksic 1980), and thus, allows comparisons Altogether 689 individual prey were identified from between data sets. skulls found in 557 owl pellets, resulting in 1.24 prey per pellet. However, estimates of the minimal number of Materials and Methods specimens based on cranial and postcranial bones accounted for 1.81 animals pellet. Owl pellets were collected from two localities in central per The Barn Owl fed Chile (El Alamo and Los Maitenes) during field studies mainly on mammals (98.1%), or more precisely on ro- conducted in January and March 1998. At both localities. dents (96.4%); the remaining 3.6% consisted of marsu- Barn Owls were observed using the roosts from which pials (1.15%), lagomorphs (0.6%), birds (1.15%), and the pellets were collected. The study site at El Alamo insects (0.7%). A total of 12 mammal species was iden-

(36°11'S, 72°24'W) comprised mainly open vegetation tified, of which 10 were rodents (Table 1). Furthermore, (meadows grazed by cattle, goats, and sheep) with many remains of eight birds, and elytra and chitin shells of five shrubs and relatively complete vegetation cover (80— beetles (Coleoptera) were found in the prey. Diet and scattered fields. The landscape inter- 100%) was breadths calculated for the broad prey categories mam- spersed with forest fragments (<20%). A total of 318 pel- mals, birds, and insects were comparable for both study lets were collected in abandoned barns at six sites near sites (Bobs = 1.04 for El Alamo and Los Maite- settlements within an area of ca. 80 km^. nes, respectively), and thus, yielded low standard niche At Los Maitenes (32°46'S, 7l°27'W), 239 pellets were breadths (B^f = 0.026 and 0.021 for El Alamo and Los collected in and nearby roosts that were located in the Maitenes, respectively) walls of a gorge, ca. 3 km from the nearest village. The Mammalian prey composition differed between the five sampling sites were located within a radius of ca. 5 km. This area was contaminated by sulphur dioxide and two localities (Table 1). Differences in the consumed arsenic emitted by an adjacent copper-processing refin- prey across the respective rodent families were significant (X^-test; P < 0.001). Whereas the cricetine rodents {Au- ery (J. Bustamente, Empresa Nacional de Minera Ven- tanas, pers. comm.) ca. 6 km from the sampling site. The liscomys micropus, Oligoryzomys longicaudatus, and Phyllotis vegetation was poorly developed with only a few shrubs, darwini) were more abundant in the owl’s diet from Los a reduced vegetative ground cover (<20%), and the soil Maitenes than in pellets originating from El Alamo, the did not contain geophytes (Begall and Gallardo 2000). reverse was true for Abrothrix longipilis (Table 1). Because The land has not been used for agriculture for at least the body mass of the respective species ranged between two decades. 30-70 g, the distribution of prey according to body mass I dissected pellets after soaking them in water, and (Fig. 1) shows a slightly higher amount of medium-sized mammalian skulls were identified using the key by Reise prey (<70 g) for Los Maitenes. Barn Owls from El Alamo (1973). In the case of uncertainty, skulls (especially seemed to take heavier prey like Rattus rattus or Octodon teeth) were compared with specifications and drawings bridgesi, with the latter being absent in Los Maitenes. The by Osgood (1943) and for cricetine rodents with an on- fossorial coruro {Spalacopus cyanus) was found more of- line key (Huiha-pukios Limitada 2002). Scientific nomen- ten in pellets from Los Maitenes (7.8%) than in the clature followed Jaksic (1997) for vertebrates. southern locality El differences Prey per pellet was estimated by summing up the num- Alamo (2.0%). The of bers of identified individual prey animals divided by the mammalian prey composition in the diet of the Barn Owl total number of pellets analyzed. Calculations of the min- resulted in significantly lower GMWP at Los Maitenes imum number of specimens per pellet were derived from (54.4 ± 25.3 g) in comparison to El Alamo (66.1 ± 36.4, the maximum number of either left or right elements of P< 0.001). cranial and postcranial bones (Lyman et al. 2003). Discussion Diet breadth (Bq^s) was calculated using the term

(Ef=i with pj being the fraction of prey category i One of the sampling localities (Los Maitenes) lies with- (Levins 1968). This index can yield values ranging be- in the geographical range of sampling localities of two = tween 1-3 (according to N three prey categories: mam- previous studies addressing the diet of the Barn Owl m mals, birds, insects). In addition, 1 calculated and stan- central Chile (Jaksic and Yanez 1979, Herrera and Jaksic dard niche breadths according to the equation B,, = 1980). In these studies, a slightly different Barn Owl prey - ~ B^;„) (Colwcll and Futuyma (B„bs Bmin)/(Bn,ax spectrum was found compared to the present findings 1971). Geometric mean weight of prey (GMWP) was cal- Nevertheless, both this study and the previous ones re- culated using the formula GMWP = antilog pi log vealed that the most important prey (>50%) consisted TO,) where p, is defined as above and W; is the mass of of Phyllotis darwini and Oligoryzomys longicaudatus. While prey category i. Data on body mass of mammalian prey Herrera and Jaksic (1980) found Al/rocoma bennetti and were obtained from Begall et al. (1999) for Spalacopus Octodon degus in the diet of Chilean Barn Owls with pro- cyanus, from Bedford and Eisenberg (1992) for Auliscomys portions of respectively, these rather micropus and Octodon sp., and from Herrera and Jaksic 4% and 3%, large (1980) for the remaining taxa. Means are given as x ± octodontoids (body mass of adults > 200 g) were absent SD (standard deviation), and mean prey sizes were com- in pellets that I had analyzed. Also chiropteran skulls, pared using Kest. that Herrera and Jaksic (1980) found in low frequencies March 2005 Short Communications 99

Table 1. Prey of Barn Owls at two study sites from central Chile (El Alamo and Los Maitenes). Data on body mass of mammals were taken from Begall et al. (1999) for Spalacopus cyanus, from Bedford and Eisenberg (1992) for Auliscomys micropus and Octodon sp., and from Herrera and Jaksic (1980) for the remaining taxa.

Body Mass El Alamo Los Maitenes

Species ( g) N{7o) N(%)

Thylamys elegans (elegant fat-tailed opossum) 40 7 (2.0) 1 (0.3)

Oryctolagus cuniculus (juv.) (old-world rabbit) 180 3 (0.8) 1 (0.3) Mus musculus (house mouse) 17 6 (1.7) 16 (4.8) Rattus rattus (black rat) 158 34 (9.6) 3 (0.9) Abrothrix longipilis (long-haired grass mouse) 76 39 (11.0) 2 (0.6) Abrothrix olivaceus (olive-grass mouse) 40 38 (10.7) 23 (6.8) Auliscomys micropus (southern big-eared mouse) 73 2 (0.6) 18 (5.4) Oligoryzomys longicaudatus (long-tailed rice rat) 45 78 (22.0) 120 (35.8) Phyllotis darwini (Darwin’s leaf-eared mouse) 66 72 (20.3) 113 (33.7) Octodon bridgesi (bridge’s degu) 93 60 (17.0) 0 (0.0) Octodon lunatus (moon-toothed degu) 233 0 (0.0) 2 (0.6) Spalacopus cyanus (coruro) 90 7 (2.0) 26 (7.8) (Bodents, unidentified) 2 (0.6) 3 (0.9) (Birds, unidentified) 4 (1.1) 4 (1.2) (Insects, unidentified) 2 (0.6) 3 (0.9) Total 354 335

(<1%) were not present in the samples from El Alamo prey availability. However, I did not assess availability of or Los Maitenes, a difference which may be related to a prey by trapping except for Spalacopus cyanus (Begall and larger sample size in the earlier study. On the other Gallardo 2000; see below). Nevertheless, different fre- hand, the cricetid rodent Auliscomys micropus was present quencies of Oligoryzomys longicaudatus, Phyllotis darwim, at Los Maitenes (5.4%) as well as at El Alamo (0.6%), yet and Abrothrix olivaceus found in the pellets from the two absent in previous studies (Jaksic and Yanez 1979, Her- study sites may be related to prey availability. Bodent out- rera and Jaksic 1980). breaks in the above mentioned species occur at regular The differences between prey compositions found at intervals and may depend on bamboo flowering, rainfall El Alamo and Los Maitenes may be due to differences in peaks, but also on density-dependent factors (Gallardo and Mercado 1999, Lima and Jaksic 1999, Jaksic and Lima 2003). 90 Other striking differences between the two sampling 80 > localities with Octodon bridgesi (El £ were found Alamo' Q. 70 17.0%; Los Maitenes: 0%) and Abrothrix longipilis (11.0% 60 I versus 0.6%). While Octodon bridgesi is absent at Los Mai- t 50 tenes (and the surrounding area), Abrothrix longipilis is 0 ® 40 most common in moister areas (like El Alamo) with a O) 1 30 high proportion of shrub and litter cover (Bedford and 0) o 20 Eisenberg 1992) —conditions that are absent at Los Mai- 0) tenes. Furthermore, Abrothrix longipilis was also reported 0- 10 to exhibit cyclic populations (Murua et al. 2003) that may 0 have contributed to differing frequencies of this species < 30 g 30 - 69 g 70 - 1 00 g > 1 00 g between the study sites. Higher amounts of Rattus rattus Body Mass Classes remains in pellets from El Alamo (9.6% versus 0.9%) cer-

Figure 1. Percentage of prey in body mass taken by tainly indicated the close association of the rat with hu- Barn Owls from two localities from central Chile (white mans. bars represent samples from Los Maitenes, black bars Skulls of Spalacopus cyanus in pellets analyzed by Her-

samples from El Alamo) . Data on body mass were taken rera and Jaksic (1980) accounted for 0.8% of the Barn from Begall et al. (1999) for Spalacopus cyanus, from Bed- Owl diet even a smaller fraction than at El Alamo (2%) ford and Eisenberg (1992) for Auliscomys micropus and during the current study. In contrast to these findings, Octodon sp., and from Herrera and Jaksic (1980) for the Spalacopus cyanus accounted for 7.8% of the Barn Owl remaining taxa. diet at Los Maitenes. This pattern was surprising because 100 Short Communications VoL. 39, No. 1

at both study sites (Los Maitenes and El Alamo), at least mente los resultados obtenidos con las caracteristicas de five colonies of Spalacopus cyanus were found in imme- ambos habitats. La region de El Alamo consistio princi- diate vicinity (<2 km) of sampled roosts. Furthermore, palmente en campos cultivados y prados, mientras que la mean colony sizes were similar at both localities (Begall region de Los Maitenes se caracterizo por presentar una et al. 1999, Begall and Gallardo 2000) suggesting similar cubierta vegetal escasa, encontrandose fuertemente afec- population densities. Perhaps low vegetation cover and tada por la polucion generada por la presencia de in- absence of geophytes at Los Maitenes force Spalacopus to dustrias de cobre en las cercanias. En ambas areas de forage above ground (on leaves of Convolvulus arvensis) estudio, T. alba mostro una amplitud de dieta estrecha, more frequently, and thus, exposing them to greater pre- representando los mamiferos un 98% del total de presas. dation pressure. In contrast, at El Alamo Spalacopus cy- Sin embargo, la composicion de la dieta vario marcada- anus spent most time underground foraging on bulbs of mente entre los dos sitios de estudio, encontrandose una the geophyte Dioscorea longipes (Begall and Gallardo mayor frecuencia de roedores fosoriales de gran tamano

2000) . Despite the absent underground-food resource at en areas alteradas que en aquellas areas que presentaban Los Maitenes, Spalacopus cyanus maintains its typical com- una cubierta vegetal densa. Finalmente, los tamanos de plex burrow network presumably to avoid even higher las presas en la regi6n de Los Maitenes fueron menores levels of predation. que los obtenidos en la region de El Alamo. Although there were several noticeable differences be- [Traduccion de los autores] tween the two foraging habitats. Barn Owls seemed to be equally abundant in both areas and exploited a similar Acknowiedgments diet mammalian-prey-based diet with comparable I thank Julio Montes who helped collect pellets. Fredy breadths. This finding indicated that sufficient mamma- Mondaca (Universidad Austral de Chile, Valdivia) helped lian prey was also available at the disturbed area of Los in identifying skulls of Chilean small mammals. I greatly Maitenes for Barn Owls and corroborates that this species appreciated help by Oliver Erdmann and Julia Baron specializes on mammalian prey. Long-term studies byjak- (University of Duisburg-Essen) for laboratory assistance, and Hynek Burda, Ana Trejo, and two anonymous re- sic et al. (1992, 1993a) revealed that if mammalian prey viewers for comments on the manuscript. decreases. Barn Owls tend to abandon the area rather than shift toward non-mammalian prey as seen in some Literature Cited other predator species (e.g., Bednarz and Dinsmore

1985, Selas 2001). Bednarz, J.C. and J.J. Dinsmore. 1985. Flexible dietary The results of this study showed that Chilean Barn response and feeding ecology of the Red-shouldered Owls took prey of medium body mass. Even the mean Hawk, Buteo lineatus, in Iowa. Can. Field-Nat. 99:262- value calculated for the study site at Los Maitenes 264. Begall, S. and M.H. Gallardo. 2000. Spalacopus cyanus (GMWP = 54.4 g) was almost twice as high as the value calculated for prey of Barn Owls from Chilean Patagonia (Octodontidae, Rodentia): an extremist in tunnel

(Iriarte et al. 1990). Higher abundances of large animals constructing and food storing among subterranean like Rattus rattus and Octodon bridgesi at El Alamo may mammals./. Zool. (Lond.) 251:53-60. have led to significantly higher mean prey mass at this , H. Burda, and M.H. Gallardo. 1999. Reproduc- locality (GMWP = 66.1 g). Studies of White-tailed Kites tion, postnatal development, and growth of social co- {Elanus leucurus) in central Chile revealed a similar pat- ruros, Spalacopus cyanus (Octodontidae, Rodentia) tern (Schlatter et al. 1980). They found that prey taken from Chile./. Mammal. 80:210-217. in the undisturbed babitat was significantly heavier than Colwell, R.K. and D.J. Futuyma. 1971. On the measure- prey taken at the disturbed area. Schlatter and colleages ment of niche breadth and overlap. Ecology 52:567- related the higher proposed that kites from anthropo- 576. genically-disturbed areas may have had access to more Fulk, G.W. 1976. Owl predation and rodent mortality a prey due to greater prey abundance or higher prey vul- case study. Mammalia 40:423—427. nerability. Whereas, I suggest there was not higher prey Gallardo, M.H. and C.L. Mercado. 1999. Mast seeding abundance in Los Maitenes due to lower habitat quality. of bamboo shrubs and mouse outbreaks in southern

Rather, I assume that higher prey vulnerability at Los Chile./. Neotrop. Mammal. 6:103-111. Maitenes may be supporting the current Barn Owl pop- Herrera, C.M. and F.M. Jaksic. 1980. Feeding ecology of ulation. the Barn Owl in central Chile and southern Spain, a comparative study. Auk 97:760-767. ECOLOGIA DE ALIMENTACION DE TYTO alba EN el CENTRO Huina-pukios Limitada. 2002. Clave de indentificacion DE Chile y su Relacion con el Habitat de Caza anatomica oseo-craneal para generos de cricetidos www.geocities.com/biodiversidadchile/cricetch.htm

Resumen.—Se comparo la composicion de la dieta de Iriarte, J.A., W.L. Franklin, and W.E. Johnson. 1990. Tyto alba en dos localidades de la region central de Chile Diets of sympatric raptors in southern Chile./. Raptor (El Alamo y Los Maitenes), relacionandose posterior- Res. 24:41-46. March 2005 Short Communications 101

Jaksic, F.M. 1997. Ecologia de los vertebrados de Chile. Lyman, R.L., E. Power, and RJ. Lyman. 2003. Quantifi- Ediciones Univ. Catolica de Chile, Santiago, Chile. cation and sampling of faunal remains in owl pellets

AND M. Lima. 2003. Myths and facts on ratadas: J. Taphonomy 1: 3-14. bamboo blooms, rainfall peaks and rodent outbreaks Murua, R., L.A. Gonzalez, and M, Lima. 2003. Second- in South America. Aust. Ecol. 28:237-251. order feedback and climatic effects determine the dy- AND J.L. YAnez. 1979. The diet of the Barn Owl namics of a small rodent population in a temperate in central Chile and its relation to the availability of forest of South America. Popul. Ecol. 45:19-24. prey. Auk 96:619—621. Osgood, W.Ff. 1943. The mammals of Chile. Field Mu- History, IL U.S.A. , J.E. Jimenez, S.A. Castro, and P. Feinsinger. seum of Natural Chicago,

1992. Numerical and functional response of predators Redford, K,H. and J.F. Eisenberg. 1992. Mammals of the to a long-term decline in mammalian prey at a semi- Neotropics: the southern cone. Vol. 2. Univ. Chicago

arid Neotropical site. Oecologia 89:90-101. Press, Chicago, IL U.S.A. la cra- , P. Feinsinger, and J.E. Jimenez. 1993a. A long- Reise, D. 1973. Clave para determinacion de los term study on the dynamics of guild structure among neos de marsupiales y roedores chilenos. Guyana predatory vertebrates at a semi-arid Neotropical site. {Tool.) 27:1-20. Oikos 67:87-96. Schamberger, M. and G. Fulk. 1974. Mamiferos del

, P.L. Meserve, J.R. Gutierrez, and E.L. Tabilo. parque nacional Fray Jorge. Idesia 3:166-179. 1993b. The components of predation on small mam- Schlatter, R.P., B. Toro, J.L. YAnez, and F.M. Jaksic mals in semiarid Chile: preliminary results. Rev. Chil. 1980. Prey of the White-tailed Kite in central Chile Hist. Nat. 66:305-321. and its relation to the hunting habitat. Auk 97:186-

, J.C. Torres-Mura, C. Cornelius, and P.A. Mar- 190. QUET. 1999. Small mammals of the Atacama Desert Selas, V. 2001. Predation on reptiles and birds by the

(Chile), y. Arid Environ. 42:129-135. Common Buzzard, Buteo buteo, in relation to changes

Levins, R. 1968. Evolution in changing environments: in its main prey, voles. Can. J. Zool. 79:2086-2093. some theoretical explorations. Princeton Univ. Press, SiMEONE, A.C. 1995. Ecologia trofica del bailarin Elanus Princeton, NJ U.S.A. leucurus y la lechuza Tyto alba y su relacion con la in- Lima, M. and F.M. Jaksic. 1999. Population dynamics of tervencion humana en el sur de Chile. Tesis de licen- three Neotropical small mammals: time series models ciatura, Univ. Austral de Chile, Valdivia, Chile. and the role of delayed density-dependence in pop- 21 2004 ulation irruptions. Aust. J. Ecol. 24:25-34. Received 11 February 2004; accepted November Letters

Iverson (2004) on Spotted Owls and Barred Owls: Comments on Methods AND Conclusion^

The late W.F. Iverson recently examined whether reproductive success of northern Spotted Owls {Strix occidentalis caurina) was negatively associated with the presence of northern Barred Owls {Strix varia varia) during 1990—92 m Res. the Mt. Baker-Snoqualmie National Forest, Washington (Iverson 2004, J. Raptor 38:88-91). He compared reproduction at six Spotted Owl territories where no Barred Owls were detected versus 13 Spotted Owl territories where Barred Owls were detected within 2-5 km of the activity centers. He concluded that Spotted Owl reproductive success (defined as having fledged >1 young in 3 yr) was unaffected by Barred Owl presence. However, Iverson used statistical analysis procedures that rendered the conclusion questionable. Specifically, the sample size of 19 was too small to subject to the statistical test used—the G-test. The G-test uses the chi-square distribution for null-hypothesis expectations (Zar 1984, Biometrics, Prentice Hall, Inc., Englewood Cliffs, NJ U.S.A; Sokal and Rohlf 1995, Biometry, W.H. Freeman and Co., New York, NY U.S.A.). Biometricians commonly state that the G-test should not be used if any expected value for a given category <1 or if >20% of the expected categorical values <5 (e.g., Zar 1984). Sokal and Rohlf (1995) further recommend that each expected value should be >5 when using a G-test. The expected categorical values based on Table 1 in Iverson (2004), obtained by dividing the product of the corresponding row and column totals by N, yields: 6.84 sites with reproduction and with ^1 Barred Owl detection; 6.16 sites without reproduction and with ^1 Barred Owl detection; 3.16 sites with reproduction and without a Barred Owl detection; and 2.84 sites without reproduction and without a Barred Owl detection. Two (50%) of the four expected values <5; consequently, the sample size was too small to compare reliably against the chi-square distribution. Furthermore, approximately one-third of the sites should have been excluded from testing. Iverson (2004) “defined reproductive success as the production of young in one or more survey years’’ (p. 88) and “compared reproductive success of Spotted Owl pairs with and without Barred Owls’’ (p. 89). However, six of the 19 sites were not occupied by potential breeding pairs of Spotted Owls during any of the 3 yr of study (Iverson 2004:Table 1). Four sites had single Spotted Owls for all 3 yr, one site had a single Spotted Owl in the first 2 yr and was unoccupied in the third yr, and the sixth site was unoccupied by Spotted Owls for all 3 yr. Excluding these six sites in which there was no opportunity for Spotted Owl reproduction, whether or not Barred Owls were present, would reduce the sample size from 19 to 13.

Putting aside Iverson’s statistical methods, it is possible that Barred Owls truly did not have a negative effect on reproduction of Spotted Owls in his study area during 1990-92. The four long-term demography studies of Spotted

Owls in Washington (e.g., Eorsman et al. 2003, Demographic characteristics of northern Spotted Owls {Strix occidentalis) on the Olympic Peninsula Study Area, WA, 1987-2002, Pacific Northwest Research Station, Corvallis, OR U.S.A., Hicks and Herter 2003, Northern Spotted Owl research in the central Cascade Range, WA, Plum Creek Timber Co. and Raedeke Associates, Inc., Seattle, WA U.S.A.) documented that Spotted Owl reproduction was high in 1990 and was very high in 1992. Consequently, it is likely that the factors that contributed to high reproductive success during these years, such as winter and spring weather patterns and prey abundance and availability, would have ameliorated or obscured effects of Barred Owls on reproduction of Spotted Owls during Iverson’s study. Analysis of such a complex issue may require inclusion of many years of data to capture more reproductively stressful, competitive years. Barred Owls have been increasing dramatically in numbers and distribution in Washington since their first detection in 1965 (Rogers 1966, And. Field Notes 20:74). Eor example, the percent of Barred Owl detections relative to all Spotted and Barred owl detections in the Gifford Pinchot National Eorest—the forest immediately south of the Mt

Baker-Snoqualmie National Eorest—increased 8.6% annually from 1982-2000 (Pearson and Livezey 2003, J. Raptor Res. 37:265-276). The range of the Barred Owl now nearly completely overlaps that of the northern Spotted Owl in Washington, Oregon, and California. So even if the presence of Barred Owls had not significantly affected Spotted Owl reproduction in the early 1990s, this may have changed over the past decade. Two more-recent studies have attempted to address this.

^ The views herein reflect those of the author and are not necessarily those of the U.S. Pish and Wildlife Service.

102 — .

March 2005 Letters 103

First, Kelly (2001, The range expansion of the northern Barred Owl: an evaluation of the impact on Spotted Owls. M S. thesis, Oregon State Univ., Corvallis, OR U.S.A.) addressed whether Barred Owls affected reproduction of northern Spotted Owls in five long-term Spotted Owl demographic study areas in Washington and Oregon from 1974-98. She found no significant difference in reproduction in Spotted Owl territories with versus without Barred

Owl detections within 0.8 km of the activity centers. However, Kelly (2001) allowed that “it is possible that the only reason that spotted owls were able to persist after barred owls were detected was because the barred owls moved on and settled elsewhere.” She suggested that a “multivariate model that included the number of years the barred owls

were present and the actual distance between the barred owls and spotted owls in each year” (p. 37), and “the number and reproductive status of barred owls that were detected each year, might better explain relationships

between the species” (p. 38).

Second, Anthony et al. (2004, Status and trends in demography of northern Spotted Owls, 1985-2003, U.S. Geo- logical Survey, Corvallis, OR U.S.A.) tested whether the presence of Barred Owls affected reproduction of northern Spotted Owls in 14 study areas in Washington, Oregon, and California from 1985-2003. Their “exploratory,” “coarse-

scale” (p. 19) Barred Owl covariate was the proportion of Spotted Owl territories in which Barred Owls were detected annually by study area. Their results also did not show any negative effects of Barred Owls on Spotted Owl reproduction. However, they recognized that even though “the impacts of barred owls were more likely to occur at the

territory level, the only data that were available from all of the study areas was this year-specific covariate” (p. 19), and recommended that “[a]ny barred owl covariate should be territory-specific and should be used to look at the

barred owl effect on territory occupancy as well as fecundity and survival of spotted owls” (p. 69) Recent studies have shown negative effects of Barred Owls on northern Spotted Owl survival (Anthony et al. 2004) and territory occupancy (Gremel 2003, Spotted Owl monitoring in Olympic National Park: 2003 annual report,

Olympic National Park Service, Port Angeles, WA U.S.A.; Kelly et al. 2003, Condor 105:45-53; Pearson and Livezey 2003). To test whether Barred Owls also negatively affect the reproductive success of Spotted Owls who survive and stay on their territories despite the presence of Barred Owls may require long-term studies with sufficient sample

sizes employing methods such as those recommended by Kelly (2001) and Anthony et al. (2004).

I thank B. Livezey, E. Forsman, E. Kelly, S. Gremel, S. Courtney, R. Pearson, T. Fleming, D. Laye, and D. Varland for encouragement and review. Kent B. Livezey (e-mail address: [email protected]), U.S. Fish and Wildlife Ser- vice, Western Washington Fish and Wildlife Office, 510 Desmond Drive, Lacey, WA 98503 U.S.A.

Received 28 June 2004; accepted 27 December 2004

Using a Portable, Anchor-bolt Ladder to Access Rock-nesting Osprey

Successful and safe captures of raptors, and access to nestlings is an important component of long-term ecological studies. Capture of adults and nestling Ospreys (Pandion haliaetus) and Bald Eagles (Haliaeetus leucocephalus) at the

nest site can be quite difficult. Often, it involves climbing tall, solitary structures to access nests. Capture methods for these species are usually dictated by the type of nesting structure, which include trees, transmission line structures,

utility poles, artificial platforms, and towers (Bent 1937, Life histories of North American birds of prey, Part 1, Natl. Mus. Bull. 170, Washington, DC U.S.A.; Poole 1989, Ospreys: a natural and unnatural history, Cambridge Univ. Press, Cambridge, U.K.). Rock islands, isolated boulders, and inland rock pillars are used to a lesser extent by both species (Bent 1937, Bider and Bird 1983, Pages 223-230 in D.M. Bird [Ed.], Biology and management of Bald Eagles and Ospreys, Harpell Press, Ste. Anne de Bellevue, Quebec, Canada). However, because Bald Eagles and Ospreys have

high nest-site fidelity (Buehler 2000, In A. Poole and F. Gill [Eds.], The birds of North America, No. 506. The Birds of North America, Inc., Philadelphia, PA U.S.A.; Poole et al. 2002, In A. Poole and F. Gill [Eds.], The birds of North America, No. 683. The Birds of North America, Inc., Philadelphia, PA U.S.A.), nests established on rock structures are potential candidates for the installation of permanent access equipment. Herein, we describe a technique that we developed to quickly and safely access raptor nests built on large rock structures to capture and tag adult and nestling Ospreys. Specifically, we describe the use of a portable, anchor-bolt ladder to access an Osprey nest on a 10-m high inland-rock pinnacle. 104 Letters VoL. 39, No. 1

Figure 1. Portable anchor-bolt ladder used in central Labrador in 2002 to access a rock-nesting Osprey (A = boltholes 12.7 ram diameter, B = brackets for attachment to rock surface, C = alternate ladder steps angled at 10 degrees).

We accessed the Osprey rock-nest site using a Bell 206L helicopter capable of carrying four passengers and pilot, while ensuring ample space to carry several sections of ladders, capture equipment, and assembly tools. We accessed the Osprey nest 1-2 wk before fledging.

We constructed five, 150-cm-long sections of portable ladders composed of 5-cm square iron stock that was 3 2- mm thick with five alternating steps (Fig. 1). Ladder steps, 30-cm long and spaced 40-cm apart, were welded to the main support angled up at 10 degrees with a 2. 5-cm edge plate at the end to prevent foot slippage. Each ladder section had two attachment brackets composed of flat iron 6-cm wide, 45-cm long and 3.2-cm thick offset 10-cm from the attached surface to permit foot clearance from the rock surface. Both brackets had two, 12.7-mm diameter holes, one drilled at each end for attachment to the rock surface. Each ladder weighed ca. 10 kg and was spray-painted orange-gold using rust-inhibiting-metal spray paint to camouflage the ladder against the side of the lichen-covered rock.

We secured each ladder section using four (two per bracket) 9.5-mm diameter, 7. 6-cm long galvanized Redhead® (American Bolt and Nut Co., Inc., Chelsea, MA U.S.A.) wedge-anchor bolts. Bolt holes were drilled into the face of the rock using an electric-rotary-hammer drill powered by a portable 700 W gas-powered generator via a 15-m electric- extension cord. Brackets were secured on each side by a single bolt tapped into place using a small sledgehammer and cemented using a waterproof adhesive. The lowest ladder section was attached 1 .5 m above the ground to prevent access by potential terrestrial predators. Ladder placement was staggered to both conform to the shape of the rock face and to detract from the enhanced visibility of a linear configuration. On 3 September 2002, we installed five sections of ladder to access an Osprey nest (53°48.25'N, 63°3.5.64'W) on a

10-m high inland-rock pinnacle (Fig. 2). It took ca. 45 min to attach the sections on the rock. The nestlings remained in the nest bowl or on the edge of the nest during the installation of the access structure. Once the ladder structure was attached, it took <5 min to access the nest and remove the two nestlings for processing. Adult Ospreys departed the nest upon our arrival and circled the nest site for ca. 10 min, then perched in nearby trees. Both adult Ospreys defended the nest during nestling removal, and then returned to their respective perches while the nestlings were processed for ca. 80 min. Nestlings were returned to the nest once banded, measured, and 35 g solar-satellite trans- March 2005 Letters 105

Figure 2. Rock pinnacle with five anchor-bolt ladder sections attached to provide access to an Osprey nest with two young in central Labrador, 3 September 2002. Photo by D.K. Laing. —

106 Letters VoL. 39, No. 1 mitters (Microwave Telemetry Inc., Columbia, MD U.S.A.) were attached. Adults defended the nest again during replacement of nestlings into the nest and returned to the nest immediately after our departure from the nest area. Both young fledged successfully and both adults returned to the nest site the following year and defended their territory but did not produce young. This breeding failure was correlated with lower productivity that was observed throughout the area in 2003, possibly due to poor spring weather conditions (T. Chubbs unpubl. data). Although the anchor-bolt ladder did not deter adults from returning to the nest site, additional monitoring would be necessary before a reasonable impact assessment of the ladder on Osprey productivity can be made.

Cost is an important factor to consider when using anchor-bolt ladders over conventional climbing techniques using experienced, qualified climbers in remote areas. The associated hardware and welding costs were ca. $80 U S per 150-cm ladder section. Rental costs for installation equipment were ca. $40 U.S. per day. We required a helicopter to access our remote site at a cost of approximately $2000 U.S. (ca. $1000 U.S./hr). Our technique also offers permanent access at nest sites with high reoccupancy rates, at no additional costs for future nest visits during subsequent years. In our particular situation, the utilization of a permanent ladder was appropriate for a remote-inaccessible area that would be accessed repeatedly during our study. We do not advise using this type of access structure where there IS human access or predators capable of accessing the nest or where this would bias study results. This technique proved valuable, not only as a tool for accessing nestlings, but as a mechanism for quick access to retrieve trapped birds, lessening the chance of injury and stress on the birds. In areas that are relatively accessible, alternative techniques involving climbing and the attachment of a static rope may be more economical. In our situation, professional climbers were unavailable locally and the travel and contract costs of acquiring such expertise were prohibitive. We recommend that fall-safety equipment be used when employing anchor-bolt ladders to scale any high rock face. To eliminate disturbance to raptors, access structures should be installed where possible on known nesting rocks during the nonbreeding season. Preinstalled access structures will decrease the disturbance time associated with the use of climbing equipment and negate the requirement for experienced climbers. We recommend that in regions where access by predators may be of greater concern, the bottom ladder section be temporarily attached using bolts or a quick release mechanism. Researchers could carry the bottom section to each nest site, further reducing the set up cost at each site by $80 U.S. Once the study has concluded, ladder sections can be removed from rock surfaces, returning natural aesthetics to sites. Our technique was effective for acces.sing Osprey nests and may be applicable to a variety of studies where the scaling of rocks or low cliffs is required to capture raptors.

We thank M.S. Martell and J. Brazil for advice on project development. We thank G. Baikie of CFL Co. who discovered the rock pinnacle. We thank L. Elson for help in the field and for drafting the figure. RG. Trimper assisted in the field. We acknowledge the support of the Goose Bay Office, Department of National Defence, McGill University, and the Department of Tourism, Culture and Recreation (Endangered Species and Biodiversity Section). Care and handling of raptors was approved by McGill University Animal Care and Use Committee protocol 4661 (May 2002-0ctober 2002) and Newfoundland and Labrador, Endangered Species and Biodiversity Section Permit dated 12 July 2002. Finally, we would like to thank J. Bednarz, M. Fuller, E. Jacobs, and an anonymous referee for their helpful comments. Tony E. Chubbs (e-mail address: [email protected]), Department of National Defence, 5 Wing Goose Bay, Box 7002, Station

A, Happy Valley—Goose Bay, NL, AOP ISO, Canada; Matthew J. Solensky, 9979 Filhnore Street NE, Blaine, MN 55434, U.SjU, Dawn K. Laing and David M. Bird, Avian Science and Conservation Centre, McGill University, 21 HI Lakeshore Road, Ste. Anne de Bellevue, PQ H9X 3V9, Canada; and Geoff Goodyear, Universal Helicopters Newfoundland and Labrador Ltd., Box 529, Station C, Happy Valley—Goose Bay, NL, AOP ICO, Canada.

Received 17 March 2004; accepted 25 October 2004

Attempted Predation on a Large-tailed Nightjar {Caprjmulgus macrurus) by an Eastern

Marsh-Harrier ( Circus spilonotus) in Coastal Vietnam

This note describes a predation attempt on a Large-tailed Nightjar {Caprimulgus macrurus) by an Eastern Marsh- Harrier {Circus spilonotus) at Nha Trang Airport (109°1U0"E, 12°14'0"N), Vietnam. Observations took place from 0650-0700 H on 28 February 2004. — .

March 2005 Letters 107

An adult male Eastern Marsh-Harrier was observed slow quartering at varying heights (between 2-10 m above the ground) over the airport terrain of concrete interspersed with overgrown grass and scrub. I observed no predation attempts within the first 5 min of observations. The marsh-harrier then glided very low (1-2 m above ground), braked abruptly in flight, almost turning over, and dropped toward the ground. The apparent attack was unsuccessful, and the presumed intended prey, a Large-tailed Nightjar, flew from the exact location where the marsh-harrier landed and rose rapidly to a height of ca. 10-15 m. The marsh-harrier remained grounded for 1-2 sec and did not actively pursue the nightjar, which flew eastward at a constant height (10-15 m) toward the coast some 80-100 m away and out of sight. The marsh-harrier continued its systematic quartering ca. 3 sec after its failed strike, but no further predation attempts were made in the following 5 min.

The Eastern Marsh-Harrier is a medium-sized raptor (47—55 cm in body length) that has been described as an opportunistic hunter, capturing “disabled aquatic birds, or those caught unawares (and) small terrestrial passerines” as well as rodents (del Hoyo et al. 1994, Handbook of the birds of the world, Vol. 2, Lynx Editions, Barcelona, Spain)

Fefelov (1996, Russ. J. Ornithol. 5:41-46) found that birds constituted 20% of the diet by number in Russia, although the total mass of birds caught exceeded that of mammals because the main avian prey taken were relatively large ducks and waders (Fefelov 2001, Ibis 143:587-592). Similarly, Hirano and Yasui (2001, Strix 19:43-47) found feathers of ducks {Anas spp.) in 22.6% of Eastern Marsh-Harrier pellets analyzed in Japan, with an additional 24.9% of pellets containing the remains of unidentified birds. However, detailed studies of the diet of this species are lacking, particularly from southeastern Asia (Simmons 2000, Harriers of the world: their behaviour and ecology. Oxford Univ. Press, Oxford, U.K.). Fefelov (2001) found that male Eastern Marsh-Harriers prefer smaller prey than do females and although Large- tailed Nightjars (body length 25-29 cm, wingspan 53-56 cm) are only slightly smaller than aquatic birds, they are substantially lighter (54-72 g) (del Hoyo et al. 1999, Handbook of the birds of the world, Vol. 5, Lynx Editions, Barcelona, Spain; Higgins 1999, Handbook of Australian, New Zealand, and Antarctic birds, Vol. 4, Oxford Univ Press, Melbourne, Australia). Del Hoyo et al. (1994) noted that larger birds taken by the closely-related Western ,” Marsh-Harrier ( Circus aeruginosus) “tend to be those that are vulnerable (e.g., ducks that are wounded or in eclipse) although Ring-necked Pheasants {Phasianus colchicus) were common prey in some areas (Ferguson-Lees and Christie 2001, Raptors of the world, Christopher Helm, London, U.K.). In a comprehensive review of the diet of the Swamp Harrier (Circus approximans\ which forms part of a superspecies with C. spilonotus, C. aeruginosus, and a number of other harriers; del Hoyo et al. 1994) in Australasia, based both on detailed studies (e.g., Baker-Gabb 1984, Aust. Wild Res. 11:517-532) and incidental records, no nocturnal birds were recorded (Marchant and Higgins 1993, Handbook of Australian, New Zealand, and Antarctic birds, Vol. 2, Oxford Univ. Press, Melbourne, Australia). Although Eastern Marsh-Harriers are likely to use a combination of visual and auditory cues to locate prey (as shown for the closely related Swamp Harrier; Baker-Gabb 1993, Pages 295-298 in P. Olsen [Ed.], Australian raptor studies, Australasian Raptor Association, Melbourne, Australia) it is interesting that a nightjar, which is both well camouflaged and usually still and silent during full sunlight, was detected. Holyoak (2001, Nightjars and their allies: the caprimulgiformes, Oxford Univ. Press, Oxford, U.K.) describes a “remarkable dearth of information on the predators ... of Caprimulgiformes.” No predators of the Large-tailed Nightjar were documented by either del Hoyo et al. (1999), Higgins (1999), or Holyoak (2001). Robinson (2000,

Bird Observer 806:26-28) flushed the species from the rainforest floor in North Queensland, Australia, after which it was pursued (but not taken) by a Grey Goshawk (Accipiter novaehollandiae) Elsewhere, a review of the literature of predation on the European Nightjar (Caprimulgus europaeus) by Marechal (1989, het 37(6):27l-273, cited in Holyoak 2001) identified five diurnal raptors as predators, including the Northern Harrier (Circus cyaneus). Wang et al. (1995,/. Field Ornithol. 66:400-403), speculated that two radio-tagged Common Poorwills (Phalaenoptilus nuttallit) had been taken by Northern Harriers (Circus cyaneus hudsonius) in Canada. This observation at Nha Trang furthers Holyoak’s (2001) summation that the few records in the literature for other nightjar species suggests a similar mixture of predation from hawks, large falcons, owls, mammals, and reptiles. When flushed in Australia, Large-tailed Nightjars usually “rise abruptly, fluttering and gliding low and erratically away through cover, often for 20-30 m” (Higgins 1999:1028). The extended escape flight observed at Nha Trang may have been due to the sparse cover present at the airport and the agility of the marsh-harrier at low heights. Given that both birds are relatively common during winter in Vietnam and other parts of southeastern Asia

(Nguyen Cu et al. 2000, Chim Viet Nam, BirdLife International Vietnam Programme, Hanoi, Vietnam; Robson 2000, A field guide to the birds of south-east Asia, New Holland, London, U.K.), such interactions may occur more frequently in open environments than reflected in the published literature.

I thank Grant Palmer, Mark Antos, Paul McDonald, and two anonymous referees for comments on the manuscript. James A. Fitzsimons (e-mail address: [email protected]). School of Ecology and Environment, Deakin University, 221 Burwood Highway, Burwood, Victoria 3125, Australia.

Received 6 May 2004; accepted 22 November 2004

Associate Editor: Michael I. Goldstein —

108 Letters VoL. 39, No. 1

Red-tailed Hawk Depredates Mississippi Kite Nestling at Dawn

Nesting ecology and demographics of the Mississippi Kite {Ictinia mississippiensis) remain unstudied in the southeastern coastal-plain states east of the Mississippi River. The Mississippi Kite recently has expanded its breeding range eastward into peninsular Florida, where it now nests as far south as Levy and Marion counties (Kale et al. 1992, The atlas of the breeding birds of Florida final report, Florida Game and Fresh Water Fish Commission, Tallahassee, FL U.S.A.; Stevenson and Anderson 1994, The birdlife of Florida, Univ. Press of Florida, Gainesville, FL U.S.A.; Florida

Fish and Wildlife Conservation Commission 2003, Florida’s breeding bird atlas; a collaborative study of Florida’s birdlife, http:/ /www,wildflorida.org/bba). I report here the details of a predation event on a Mississippi Kite nest m peninsular Florida.

On 1 June 2002, I discovered a Mississippi Kite nest in a tall (33 m) loblolly pine {Pinus taeda) tree in a suburban neighborhood in Gainesville, Alachua County, FL. The nest was a moderately compact structure of sticks and twigs located in the central fork at the top of the tree. An adult kite sat very low on the nest holding its tail at a slight angle above horizontal, indicating incubation (K. Meyer pers. comm.). During the next 6 d, I monitored the nest opportunistically (1-25 times/d for 1-5 min/visit) because it was located near my home; an adult was sitting on the nest 92% of the time. On the afternoon of 9 June, the adult on the nest was unusually active, shifting position, and turning its head frequently. Beginning 11 June, the kite attending the nest sat higher on the nest and shifted its position more frequently, while its mate frequently chased Fish Crows {Corvus ossifragus) away from the nest tree These behaviors are consistent with the onset of hatching and subsequent brooding of young (Parker 1999, In A.

Poole and F. Gill [Eds.], The birds of North America, No. 402. The Birds of North America, Inc., Philadelphia, PA

U.S.A.). On 26 June, I observed a single nestling. At 1 min after sunrise (0634 H) on 3 July, I observed an adult Red-tailed Hawk {Buteo jamaicensis) hunched over the kite nest, while both adult kites circled over the nest tree alarm-calling loudly and repeatedly. The kites repeatedly swooped over the hawk, but did not strike it. At ca. 0640 H, the hawk flew off to the west, calling once as it took flight, and carrying the remains of a nestling in its talons. One kite gave pursuit, while the other kite remained near the nest tree, calling 6-15 times per min until 0700 H. At 0700 H, the kite began calling less frequently, and at 0710 H, two crows lit in the crown of the nest tree and were not chased off. I concluded my observations at 0713 H. I do not know if the hawk forced an adult kite off the nest or if the hawk attacked the nestling while the nest was unattended. However, Mississippi Kite brooding decreases markedly 12 d after hatching

(Parker 1999), and given that the nestling would have been ca. 21-22 d old, it seems likely that the nest was unattended.

This predation observation is unusual from at least two standpoints. First, the Great Horned Owl {Bubo virginianus) has been identified as the primary predator of Mississippi Kite nestlings and adults in other parts of the kite’s range

(Parker 1999 and references cited therein). Corvids and raccoons {Procyon lotor) also are mentioned as common predators of kite eggs and nestlings (e.g., Fitch 1963, Observations on the Mississippi Kite in southwestern Kansas.

Univ. Kansas Mus. Nat. Hist. Publ. 12:503-519; Parker 1999), but 1 found no published reports of Red-tailed Hawks depredating Mississippi Kite nests. Second, avian prey items taken by Red-tailed Hawks are typically gamebirds or medium-sized passerines and less frequently waterfowl (see Palmer 1988, Red-tailed Hawk Buteo jamaicensis. Pages 96—

134 in R. Palmer [Ed.], Handbook of North American birds, Vol. 5, Yale Univ. Press, Hew Haven, CT U.S.A.; Preston and Beane 1993, In A. Poole and F. Gill [Eds.], The birds of North America, No. 52. The Birds of North America,

Inc., Philadelphia, PA U.S.A.). Killing nestlings of other raptor species appears to be a rare phenomenon. It is unknown whether this predation event resulted from a spontaneous encounter or whether the Red-tailed Hawk had observed the nest on previous occasions prior to preying upon it.

I thank S. Miller for assistance with field observations and J. Coulson, D. Leonard, K. Meyer, J. Rodgers, A. St. Pierre, J.C. Bednarz, and an anonymous reviewer for constructive comments on the manuscript. Karl E. Miller (e- maU address: [email protected]), Florida Fish and Wildlife Conservation Commission, Wildlife Research Lab- oratory, 4005 South Main Street, GainesviUe, FL 32601 U.S.A.

Received 3 February 2004; accepted 17 October 2004 — . —

March 2005 Letters 109

First Nesting of Cooper’s Hawks {Accipiter coopeeii) in New York City Since 1955

Many species of diurnal and nocturnal birds of prey breed in large cities in North America including Peregrine Falcons {Falco peregrinus). Red-tailed Hawks (Buteo jamaicensis), and Great Horned Owls {Bubo virginianus) Over approximately the last two decades, several observers have discovered Cooper’s Hawks {Accipiter cooperii) nesting in suburban and urban United States (Stablecker and Beach 1979, Inland Bird Banding 51:56-57; Boal and Mannan 1998,/. Wildl. Manag. 62:864—871). We report on two Cooper’s Hawk nests in New York City, the first documented breeding of this raptor here since 1955. Historically, from the late 19* century to the early 1940s, breeding Cooper’s Hawks were occasionally found in remote, forested sections of New York City such as in Bronx and Richmond counties (Griscom 1923, Abstract of the Proceedings of the Linnaean Society of New York 37-38:73-87; Siebenheller 1981, Breeding birds of Staten Island, 1881 1981, Staten Island Institute of Arts and Sciences, Staten Island, NYU.S.A). The last reported nests were in a large, forested park in Bronx County from 1951-55 (P.A. Buckley pers. comm.). During this time, with the use of synthetic chemicals such as DDT to control insects, a variety of raptor species declined throughout North America, including species that nested near or in cities (e.g., Herbert and Herbert 1965, Auk 82:62-94). With the banning of DDT and similar chemicals in North America, many raptor species have significantly increased

(e.g., Bednarz et al. 1990, Auk 107:96-109). Since the late 1980s, the Cooper’s Hawk has become a fairly common fall migrant and winter resident in New York City, even in Central Park in Manhattan. By the mid-1990s. Cooper’s Hawks were found breeding in all parts of New York State except New York City and Long Island (Marsi and Kirch 1998, Cooper’s Hawk. Pages 188-189 in E. Levine [Ed.], Bull’s birds of New York state, Comstock Publishing Asso- ciates, Ithaca, NYU.S.A.). Since 1999, two pairs of nesting Cooper’s Hawks have been found in New York City: in Richmond County (Staten Island) in 1999, and in Bronx County in 2001-03. When discovered in Richmond County, the male was in first-year (brown back) plumage. In 2001 at the Bronx County nest, the female was in first-year plumage, and the male was in subadult plumage (Clark and Wheeler 2001, Hawks of North America, Houghton-Mifflin Company, New York, NY US.A.). We were able to study the nest in Bronx County at the New York Botanical Garden from 2001-03. This 101 ha park is heavily used by the public, and surrounded by parking lots, four-lane streets, and two highways. The nest was situated in nonnative conifers, between 60-120 m from any tract of contiguous forest. The habitat immediately surrounding the nest site was manicured lawn with well-spaced trees, interspersed with pedestrian pathways. These raptors preyed upon small birds and the occasional mammal. Young fledged in each of the 3 yr (x = 4.0 young/yr). In the second and third years, more young fledged ca. one week earlier than compared to the first year nest. This pattern was consistent with previously-documented aspects of the nesting biology of Cooper’s Hawks (e.g., Boal 2001, Condor 103:381-385). Adult Cooper’s Hawks, presumably the same individuals that nested, were observed in tbe park throughout the winter. In spring 2004, with m^or construction 50 m from the nest, and extensive pruning of the nest tree. Cooper’s Hawks did not breed in the park. No additional reports have been received concerning Cooper’s Hawks currently nesting in other areas of New York City. Robert DeCandido (e-mail: [email protected]), Hawk

Moimtain Sanctuary, Acopian Center, 410 Summer Valley Road, Orwigsburg, PA 17961 U.S.A.; and Deborah J. Allen, The Linnaean Society of New York, P.O. Box 1452, Peter Stuyvesant Station, New York, NY 10009 U.S.A.

Received 28 May 2003; accepted 31 October 2004 Associate Editor: Clint W. Boal 0

Manuscript Referees

The following people reviewed manuscripts for the Journal of Raptor Research in 2004. Peer review plays a vital role in the publishing process and improving the quality of the Journal. The editorial staff would like to thank the following people for reviewing manuscripts this past year. The names of those who reviewed two or more manuscripts are indicated with an asterisk.

D. Andersen*, D. Bakaloudis, J. Balbontin*, B. Balen, R. Barclay, J. Bart, M. Bechard, J. Bednarz*, P. Beja, I.

Bellocq*, J. Berkelman*, S. Bertolino, K. Bildstein*, G. Blanco, P. Bloom, C. Boal, G. Boano, T. Booms, V. Bretagnolle,

J. Brunjes, D. Buehler, J. Gabot, T. Cade, S. Cananelli, J. Cartron, M. Garrete, B. Garner, E. Casado, H. Chen*, R.

Clift, M. Collopy, D. Craighead, P. Darby, D. DeAngelis, R. Dawson, S. Deem, M. DiVittorio, J. Donazar, C. Dykstra*, P. D. Ellis*, S. England, D. Evans, C. Farquhar, M. Ferrer, J. Figuerola, L. Flake, G. Foster, Galeotti*, H. Garner, J. Genot, R. Gerhardt, A. Giese*, L. Gilson, L. Goodrich, F. Gonzalez-Garcia, C. Griffith*, R. Hartely, C. Henny, M.

Herremans, W. Hodos, G. Holroyd, S. Houston*, D. Howell, G. Hunt, E. Inigo-Elias*, S, James, F. Jaskic*, D. Johnson,

R. Johnson, G. Kaltenecker, J. Keane, P. Kennedy, P. Kerlinger, L. Kiff, N. I^ellem, E. Knudsen, M. Kochert*, R

Lehman, B. Linkhart, K. Livezy, A. Lohmus, S. Manosa, L. Marches!*, B. Marcot, A. Margalida, J. Marks*, M. Martell, C. Marti, B. Martinez, K. Mazur, D. McCallum, E. McClaren, C. McIntyre, M. McGrady, B. Meyburg, K. Meyer, R

Meyer, K. Miller, B. Montevecchi, T. Morrell, J. Morrison, G. Olsen, D. Ontiveros, E. Pavez, C. Pennycuick, V. Pen- teriani, D. Pepler, M. Petersen, C. Preston, G. Proudfoot, J. Real, P. Redig, S. Redpath*, G. Ritchison*, D. Ripper, C

Rodriquez, R. Rodriquez-Estrella*, B. Rosenheld*, T. Sanchez, J. Sarasola, R. Sarno, J. Sauer, J. Schnell, J. Schmutz*,

N. Seavy, D. Serrano, S. Sherrod, J. Sikarskie, R. Simmons, J. Simonetti, R. Silvo, J. Smallwood, J. Smith*, G. Sonerud,

A. St. Pierre, R. Steidi, Y. Sun, T. Swem*, J. Telia, D. Tinkler, D. Tome*, J. Thiollay*, C. Thompson*, A. Trejo, T

Tripp, H. Ulmschneider, D.Van Nieuwenhuyse, J. Vargas, J. Wallis, K. Warnke, D. Whitacre, C. White, S. Williams, P. Wood, R. Yosef*, and K. Young.

no Buteq Toll Free: 800-722-2460 phone: 434-263-8671 Books fax: 434-263-4842 Specializing in Ornithology

Buteo Books is the largest retailer of Ornithology books in North America^ with over 2,000 in-print titles, and hundreds ofout-of-print titles available.

A FEW BOOKS ON BIRDS OF PREY AND FALCONRY Raptors of Eastern North America. BrianWheeler. Raptors of Western North America. Brian Wheeler.

Suggested Practices for Raptor Protection on Power Lines: State of the Art in 1996. Return of the Peregrine: A North American Saga of Tenacity and Teamwork. Tom Cade and William Burnham. The Peregrine Fund.

Birds of Prey: Health and Disease. Third Edition. John E. Cooper.

North American Falconry and Hunting Hawks, Eighth edition. Beebe &Webster.

Handbook of the Birds of the World. The first eight volumes of this projected sixteen-volume work are available for $195 each. Volume 2 includes diurnal raptors, Volume 3 includes owls. Volume 9 will be available August 2004. RARE AND OUT-OF-PRINT ORNITHOLOGY Buteo Books has a wide selection of used and out-of-print titles available, including rare falconry collections. Our stock changes daily, so call to check availability of that scarce title you're seeking. BIRDS OF NORTH AMERICA SERIES This series consists of individual species accounts for each of the more than 700 species which breed in the United States and Canada, including diurnal and nocturnal raptors. These illustrated reviews provide comprehensive summaries of the current knowledge of each species, with range maps and extensive list of references.

Buteo Books is pleased to offer these accoimts for $7.50 each. All 716 profiles are listed in taxonomic order on our website. Singles may be ordered by contacting Buteo Books. Shipping and handling is $4 for the first profile and $1 for each additional profile to a maximum of $10 per order.

Buteo Books; 3130 Laurel Road; Shipman, VA 22971; USA

Visit our website for more information: www.buteobooks.com A Telemetry Receiver Designed with The Researcher in Mind What you've been waiting for!

synthesized telemetry receiver that weighs less than 13 ounces. Is Finally, a highly sensitive 999 channel over all frequencies. For each animal bemg completely user programmable and offers variable scan rates frequency (to lOOHz) and channel number, but also a tracked the large LCD display provides not only the digiUl signal strength meter. Stop carrying receivers l^at a^ 7 character alphanumeric comment field and a features and performance of the new R-IOOO pocket sized the size of a lunch box or cost over S1500, The you. telemetry receiver will impress you, and the price will convlrtce

Features Include: Other .... . Band • Very high sensitivity of .148dBm to Factory tuned to any 4MHz wide segment in the 148174MHz darkness • User selectable scan rates «cn.4D-, • Illuminated display and keypad for use in low light or batteries operate the receiver for 12 hours and 1-30 seconds in 1 second steps • Rechargeable can be replaced with standard AA Alkaline batteries in the field. Both 12vdc and llOvac chargers are included.

• 6.r (IS.Scm) high. 2.6" (6.6cm) wide. 1.5" (3.8cm) deep.

• 3 year wananty

• 1 day delivery S695.00 Please specify desired 4MHz ¥xide segment in the 148-174MHZ band

Visit our website for complete specifications, operating manual and information on the R-1000 or call our toll-free number to order your receiver now.

Try the New R-2000 and YouV Be Impressed!

COMMUNICATIONS SPECIALISTS, INC. • 1-714-998-3021 • Fax 1-714-974-3420 426 West Taft Avenue • Orange. CA 92865-4296 • http;//www.com spec.com Entire U.S.A. (800) 854 0547 • Fax (800) 850-0547 2005 ANNUAL MEETING

The Raptor Research Foundation, Inc. 2005 annual meeting will be held on 12-16 October 2005 in Green Bay, Wisconsin. For more information about the meeting contact Bob Flowe (hower® uwgb.edu) or Kim McKeefry (920-465-5032).

Persons interested in predatory birds are invited to join The Raptor Researeh Foundation, Inc. (see: http://biology.boisestate.edu/raptor/). Send requests for information concerning membership, subscriptions, special publications, or change of address to OSNA, 5400 Bosque Blvd., Suite 680, Waco TX 76710, U.S.A. TheJournal ofRaptor Research (ISSN 0892-1016) is published quarterly and available to individuals for $40.00 per year and to libraries and institutions for $65.00 per year from The Raptor Research Foundation, Inc., 14377 11 7th Street South, Hastings, Minnesota 55033, U.S.A. (Add $3 for destinations outside of the continental United States.) Periodicals postage paid at Hastings, Minnesota, and additional mailing offices. POSTMASTER: Send address changes to TheJournal of Raptor Research, OSNA, P.O. Box 1897, Lawrence, KS 66044-8897, U.S.A. Printed by Allen Press, Inc., Lawrence, Kansas, U.S.A. Copyright 2005 by The Raptor Research Eoundation, Inc. Printed in U.S.A. 0 This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper).

Raptor Research Foundation, Inc.

Grants and Awards

For details and additional information visit: http://biology.boisestate.edu/raptor/rrfi.htm

Awards for Recognition of Significant Contributions.

The Tom Cade Award is a non-monetary award that recognizes an individual who has made significant advances in the area of captive propagation and reintroduction of raptors. The Fran and Frederick Hamerstrom

Award is a non-monetary award that recognizes an individual who has contributed significantly to the under- standing of raptor ecology and natural history. Submit nominations for either award to: Dr. Clint Boal, Texas Cooperative Fish and Wildlife Research Unit, BRD/USGS, Texas Tech University, 15th Street & Boston, Ag Science Bldg., Room 218, Lubbock TX 79409-2120 U.S.A.; phone: 806-742-2851; e-mail: [email protected]

Awards for Student Recognition and Travel Assistance.

The James R. Koplin Travel Award is given to a student who is the senior author and presenter of a paper or poster to be presented at the RRF meeting for which travel funds are requested. Application deadline: due date for meeting abstract. Contact: Dr. Patricia A. Hall, 5937 E. Abbey Rd., Flagstaff, AZ 86004; phone: 520-526-6222 U.S.A.; e-mail: [email protected]

The William C. Anderson Memorial Award is given to both the best student oral and poster presentation at the annual RRF meeting. The paper cannot be part of an organized symposium to be considered. Application

deadline: due date for meeting abstract, no special application is needed. Contact: Rick Gerhardt, Sage Science, 319 SE Woodside Ct., Madras, OR 97741 U.S.A; phone: 541-475-4330; email: [email protected]

Grants.

Application deadline for all grants is February 15 of each year; selections will be made by April 15.

The Dean Amadon Grant for up to $1000 is designed to assist persons working in the area of systematics (tax-

onomy) and distribution of raptors. The Stephen R. Tidly Memorial Grant for up to $500 is given to support research and conservation of raptors, especially to students and amateurs with limited access to alternative funding. Agency proposals are not accepted. Contact for both grants: Dr. Carole Griffiths, 251 Martling Ave., Tarrytown, NY 10591 U.S.A.; phone: 914-631-2911; e-mail: [email protected]

The Leslie Brown Memorial Grant for up to $1400 is given to support research and/or the dissemination of information on African raptors. Contact: Dr. Jeffrey L. Lincer, 9251 Golondrina Drive, La Mesa, CA 91941, U.S.A.; e-mail: [email protected]