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621 in I.G. Priede and S.M. Swift [EDS.], Wildlife te- MEYBURG, B.-U., X. EICHAKER, C. MEYBURG, AND P. PAI- lemetry: remote monitoring and trackingof . LLAT. 1995a. Migrations of an adult Spotted Ellis Horwood Ltd., New York, NY U.S.A. trackedby satellite.Brit. 88:357-361. BLOOM,P.H. 1987. Capturingand handling raptors.Pag- --, C. MEY•U}•G,AND J. M•HES. 2006. Annual cycle, es 99-123 in B.A.G. Pendleton, B.A. Millsap, K.W. timing and speed of migration of a pair of Lesser Cline, and D.M. [EDS.], Raptor management SpottedEagles ( pomarina) tracked by satellite. techniques manual. National Wildlife Federation, J. Ornithol.In press. Washington,DC U.S.A. MIZERA, T., G. MACIOROWSKI,AND B.-U. MEYBURG.2001. B}tOWN,L. )d,•DD. AMADON.1968. , and Fal- [Aquila clanga(Pallas, 1811) ] cons of the world. Vol. 1. Country Life Books,Felt- Pages 145-148 in Z. Glowacinski [ED.], Polish red ham, . data book on animals.Vertebrates. Panstwowe Wydaw- nictwo Rolnicze I Lesne, Warszawa, . (In Polish BUST^M•NTE,J. 1995. The duration of the post-fledging with English summary). dependence period of Ospreys(Pandion haliaetus) at Mo}tvAN,R. and F. DOBCHIES.1990. D6pendance de jeu- Loch Garten, . Bird Study42:31-36. nes Aigles de Bonelli (Hieraaetusfasciatus)apres l'en- C•, W.S. 1981. A modified dho-gazatrap for use at a vol: variations individuelles. Alauda 58:150-162. raptor banding station.J. Wildl. Manage.45:1043- RAFANOMEZANTSOA,S.A. 2000. Behavior and range move- 1044. ments during the post-fledgingdependence period of DEMENTIEV,G.P. AND N.A. GL•d)KOV. 1951. Birds of the the -Eagle (Haliaeetusvociferoides). Soviet Union. Moscow, . (In Russian). Pages113-119 in R.D. Chancellor and B.-U. Meyburg HAMERSTROM,F. 1963. The use of Great Horned in [EDS.],Raptors at risk. Hancock House and WWGBP, catching Marsh Hawks. Proc.Int. Ornithol.Cong• 13: Berlin, . 866-869. REAL,J., S. MA•OSA,AND J. CODINA.1998. Post-nestling IrANov, A.I., E.V. KozI•ov^ E.V., L.A. PORTENKO,AND A.Y. dependenceperiod in the Bonelli'sEagle (Hieraaetus TUG•mNOV. 1951. Birds of Soviet Union. Vol. 1. Iz- fasciams).Ornis Fennica 75:129-137. datelstvo Akademi Nauk SSSR, Moscow, Russia. (In Russian). Received24 November 2003; accepted5 September2005

J RaptorRes. 39(4):466-471 ¸ 2005 The Raptor ResearchFoundation, Inc.

SEASONALP^TTEm'qS OF COMMONBUZZ•mD ( BUTEO) P•tATtV• ABUNDANCEAND BEH•VIO}•IN POLLINO NATIONAL ,

MASSIMOPANDOLFI, ALESSANDRO TANFERNA, AND GIORGIAGAIBANI 1 Istitutodi Zoologia,Universitd di Urbino,via Oddi 21, 61029 Urbino,Italy

KEY WORDS: CommonBuzzard; Buteo buteo; relative abun- though roadside surveyshave well-known limitations dance;roadside surveys. (e.g.,Andersen et al. 1985,Fuller and Mosher1987, Mill- sapand LeFranc1988, Vifiuela 1997), theyremain a use- Nest-site selection and habitat use have been described ful techniquefor monitoringlocal abundanceand distri- •n the Common (Buteobuteo) by severalauthors bution of raptors (Fuller and Mosher 1987, Ellis et al. (e.g., Penterianiand Faivre 1997, Krfiger 2002, L6hmus 1990). Becauseroadside surveys are easyto conduct,they 2003, Bustamanteand Seoane 2004, Sergio et al. 2005), can be carried out at frequent intervals.Here, we present but few studies have documented annual variations in the resultsfrom monthly roadside surveysof Common Buz- abundance and habitat associationsof this (Meu- zards.Using thesedata, we examine habitat associations, nier et al. 2000). describeseasonal patterns of Common Buzzardbehavior We conducted monthly roadside surveysof Common and abundance and, in particular, discussthe effective- in a mountainous area of southern Italy. A1- ness of roadside surveysto monitor changes in abun- dance. 1 Present addressand correspondingauthor: Museo di METHODS Storia Naturale, Dipartimento di Biologia Evolutiva e Funzionale, Universit•t di Parma, Via Farini 90, 43100 The (hereafter buzzard) surveyswere Parma, Italy; e-mail address:[email protected]. it conductedfrom October2000-September 2001 in Polhno DECEMBER2005 S•4ORT COMMUNICATIONS 467

transects

Pollino National Park

I ! % .,, J ß 1

I !

l* 0,0 4,0 km I I I

Figure 1. Locationsof sevenroutes (thick dark lines) usedfor roadsidesurveys in PollinoNational Park, southern Italy, in 2000-01 (thin lines indicate the boundaries).

National Park (39ø58'N, 16ø08'E), a 1821 km9 area located and only on calm and cleardays. We did not sampleon in the southernItalian Apennines(Fig. 1). The elevation dayswith snow,rain, fog, or strongwinds. Each month, rangesfrom 170-2266m. The land usesinclude farmlands the routeswere surveyedover 4 d by meansof two cars, and woods( Quercusilex, Q. pubescens,Q. cerris)in the each one with a driver and two observers.All surveys northern sectionof the park and grasslandand beech were conductedin the morning (0900-1200 H), typically woods (Fagussylvatica) in the southernportion. Over the the best time to count raptors (Robbins1981). We drove studyperiod, the mean monthly temperaturewas 14.5øC, at a speed of 40-45 km/hr and stopped the car to con- wtth a mean of 28.8øCduring July-September and 9.7øC firm each sighting. For each buzzard detected, we re- during October-February.The annual rainfall in the 12 corded if it was flying or perched and if it was alone or mo of the surveywas 841 mm. with other buzzards.Also, we discountedany buzzard that We surveyedbuzzards along seven paved roads (Fig. 1) may haverepresented a re-sightedbird. selectedrandomly with restrictions(Caughley and Sin- We calculated the relative abundance as the number clair 1994). Specifically,we rejected routes adjoining of buzzardsseen per 100 km sampled.For abundance thoseroads previously chosen. Each road wassurveyed computationswe excludedthe stretchesof roadslined by once each mo, during the third or fourth wk of the mo trees within tunnels, forests,or villages.Therefore, al- 468 SHORT COMMUNICATIONS VOL. 39, NO. 4

Table 1. Number of Common Buzzardsrecorded along seven routes in Pollino National Park (southern Italy, 2000-01). For computation of relative abundance, we used the surveylength obtained discountingthe stretch- es of roads lined by trees or passingthrough tunnels, forests, or villages.

SURVEY LENGTH LENGTH MONTHLY MF&N (km) oF (km) OF -+SD OF ROUTES ROUTES ROUTES RELATIVE ABUNDANCE

i 57.8 40.4 11.2 + 1.8 2 18.3 18.3 10.2 q- 2.0 3 44.4 28.9 6.7 q- 2.0 4 47.3 34.0 12.7 --+ 2.7 5 38.5 38.3 7.7 + 1.6 6 43.8 24.2 20.1 +-- 5.7 7 65.1 53.6 9.3 +---1.2

though the total road length was 315.2 km, we consid- ered for analysisonly 237.6 km (surveykm in Table 1). For the analysisof buzzard habitat associations,we re- ported the sightingsas presence/absencein a 1 X 1 km UTM grid. We created a 1 km buffer on both sides of each route and we considered only buzzards observed inside this buffer. We analyzed the habitat associations within this buffer using the Corine Land Cover 1:100000 digital map (Legend level 3, Ministero dell'Ambiente e del Territorio--Ente Parco), identifying 10 land cover typeswhich we then pooled into four general vegetation cover types: (1) (cultivatedareas regularly plowed and generallyunder a rotation system),(2) het- erogeneousagricultural areas (areasprincipally occupied by agriculture, interspersedwith natural areas), (3) for- ests, and (4) shrub or herbaceous vegetation (Table 2). In each 1 X 1 km grid cellsor portions of a cell included inside the buffer, we calculated the surface of each cover type by means of a GeographicalInformation System (GIS) analysis (Geomedia Professional 2002). Buzzard habitat associationswere analyzedin four periods:Feb- ruary-April (courtship), May-July (incubation and nest- ing), August-September(post-fiedging), and October- January (winter). Although observers recorded the number of individual buzzardssighted, we only consid- ered their presence/absencein each grid cell. We used the Friedman repeated measuresanalysis of variance (F,.)to detectany difference in the relativeabun- dance among months and among periods. Using the same test, we evaluated if the number of flying or perched buzzardsvaried among months or periods. We used the Kruskal-Wallistest to detect any difference in the relative abundance among routes and the Mann- Whitney U test to ascertainwhether flying buzzardswere observed more frequently than perched buzzards.We used the arcsin-transfor•nationto convertthe proportion of sightingscomposed of buzzard groups. The Kolmo- gorov-Smirnovone-sample test (Z) was used to examine if the distribution of relative frequencieswas uniform. Finally, we used a stepwiselogistic regressionto deter- DECEMBER 2005 SHORT COMMUNICATIONS 469

4O ß Groupedand SingleBuzzards [] SingleBuzzards -•. 30

o• 25

• 20 •: •5 T • • • T • 10 • 5 o

Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 2. Monthly mean _+SDof the relative abundanceof Common Buzzardsrecorded along sevenroutes in Pollino National Park, southern Italy (2000-01). The dark columns show the relative abundancecalculated consid- ering both groupedand singleindividuals; the white columnsare the relativeabundance calculated based on single individualsonly. mine whether the probability of detecting buzzardsvar- Most buzzardsdetected (67.4%, N = 221) were alone, ied among the four cover typesin each of the periods. while 23.2% (N = 76) were paired and 9.4% (N = 31) Means are presented +SD. The nonparametric testswere were in larger groups, with a mean group size of 3.9 __+ from Siegel and Castellan (1988), and the logistic re- 0.6 individuals.The proportion of sightingscomposed of gressionanalysis followed Field (2000). All of the statis- tical testswere performed with SPSS10.0 (SPSS2000). a group of buzzards showed a uniform distribution throughout the year, ranging from 0.4 in July to 0.0 in RESULTS January (z = 1.5; N = 12; P > 0.05). No land covervariable entered the stepwiselogistic re- During the study period, we recorded 328 buzzard gressiondiscriminating between grid cellswith or without sightings.The mean relative abundanceper roadsidesur- buzzards,in any of the four periods of the year (Table vey was 11.1 ___4.4 (N= 84) buzzards/100 km (Table 1). 2). Buzzard abundance varied among months (Fr = 23.1; df = 11; P < 0.05; Fig. 2) and, marginally,among periods DISCUSSION (Fr = 7.6; df = 3, P = 0.054). In particular,a post-hoc multiple comparisons test showed that the abundance The relative abundance of the study population was wasgreater during the courtshipperiod than in the other relatively stable throughout the year, apart from a peak three periods and in the incubation-nestingperiod than during the courtshipperiod (February-April). A possible in the winter (P < 0.05 for all comparisons).However, explanation is that during the courtship period, many the relative abundanceestimates showed a high variation young buzzards return to their natal area. A high ten- for all periods(17.2 + 11.9 for courtship,10.2 ñ 5.0 for dency for philopatric movementsamong dispersershas incubationand nesting,7.2 - 4.3 for post-fledging,and been recorded both in Common Buzzards (Walls and 9.0 -+ 2.4 for winter). Kenward 1998) and other raptors (e.g., Ferrer 1993, We found no difference (X2 = 10.3; df = 6; P = 0.11) Newton et al. 1994, Carter 2001). A secondexplanation in abundanceamong routes,although the surveyroutes for the observedincrease in relative abundancemay be crosseddifferent land cover types. We detected more linked more to buzzard behavior and detectabilitythan buzzardsflying (87.2%) than perched (12.8%; U = 1.5; to variationsin actual population density.During court- N = 24; P • 0.0001). The number of perched buzzards ship, buzzardsparticipate in more aerial displaysthan in did not vary among months (Fr = 15.6; df = 11; P > other periods, and are thus more detectable.This expla- 0.05), whereasthe number of flying buzzardsdid (Fr = nation is supported by the higher proportion of flying 21.0; df = 11; P• 0.05) (Fig. 3). In addition, the number buzzardsrecorded during the courtshipperiod, particu- of flying buzzardsvaried among periods (F• = 10.8; df = larly in March, when all the detected individuals were 3; P • 0.05); during courtship,flying buzzardswere more flying (Fig. 3). numerous than in all other periods (Multiple Compari- The decreasein relative abundance during the incu- son test P • 0.05). bation and nestingperiods is probablyrelated to the fact 470 SHORT COMMUNICATIONS VOL. 39, NO. 4

60 ß Flying '• 50 [] Perched N N 03 40

• 30 o '• 20

E •o

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 3. Total number of flying and perched Common Buzzardsobserved per month during vehicle surveyscon- ducted at Pollino National Park, southern Italy in 2000-01.

that half of the breeding population were tending nests agreement could be related to the coarsescale of our or were close to their nests most of the dme. However, landscapeanalysis. However, S•tnchez-Zapataand Calvo contrary to expectations,during the post-fledgingperi- (1999) found a linkage between buzzard nest sitesand od, when flying youngjoin the adult population,the rel- some landscape characteristicsusing a coarse-scale(1. auve abundancewas not higher than that estimateddur- 200 000) land use map. ing the other periods. This could be caused by the In summary,our resultsshowed that the relativeabun- relatively inconspicuousbehavior of fledged buzzards dance of a raptor population recorded by road counts that often are perched in the immediate neighborhood may be sensitiveto temporal behavioralchanges, which of the nest for severalweeks after fledging (Tubbs 1974, ultimately affect detectability,thus biasinga potential as- Tyack et al. 1998). Moreover,because most natal dispers- sessment of seasonal variations in numbers. For this rea- al usuallyoccurs in the autumn (Picozziand Weir 1976, son, roadsidesurveys would be a coarsemethod to mon- Walls and Kenward 1998), it is possiblethat our survey itor intra-annual population changes,or to compare the methodsunderestimated fledged young during the post- relative abundancerecorded in different years,unless the fledging period. data are collected in the same time period or season.On In our study,buzzards did not show a preference for the other hand, we suggest further investigation into any land cover type during any periodsof the year.This whether roadside surveyscan be a useful tool for long- •s supportedby lack of variation among the sevenroad- term monitoring of a population when comparing the s•desurveys, although theseroutes crossed different haty same months in different years. •tats.This lack of associationwith cover type may be due to the buzzard's high plasticityand varied diet (Cramp PATRONES ESTACIONALES EN LA ABUNDANCIA RELATIVA Y EL and Simmons 1979, Sergio et al. 2002). However, S•tn- COMPARTAMIENTODE mtflEOBtfFEO EN EL PARQUENACION- chez-Zapataand Calvo (1999), Krfiger (2002), and Sergio AL POLLINO, ITALIA et al. (2005) found that buzzard breeding sites were hnked to some landscapecharacteristics, particularly for- RESUMEN.--Seestudi6 la abundancia relativa de una po- est cover.There are three possibleexplanations for this blaci6n de Buteobuteo a lo largo de 12 mesesen el Parque discrepancyin results.First, the previous studiesexam- Nacional Pollino (sur de Italia) para comparar datosen- •ned the relationship between habitat characteristicsand tre mesesy para determinar las asociacionesde h•tbitat nesting sites,while we examined the associationof indi- Realizamoscensos mensuales en carreteras a lo largo de wdual locationswith land covertype. Second,we record- siete rutas (total = 315 km). La media anual de aves ed buzzardswhen in flight or perched, whether they were detectadasfue de 11.1 _+4.4 individuos/100 km, aunque hunting or involved in other activities.Finally, the dis- este valor vari6 significativamente entre meses.Esta vana- DECEMBER 2005 SHORT COMMUNICATIONS 471 c16n probablemente refiej6 la actividad de vuelo de B. zard ( Buteobuteo) and Goshawk( gentilis). Eco- buteoy no las fiuctuaciones en el nfimero de individuos graphy25:523-532. durante el afio, ya que la mayoria de los registrostuvie- LOHMUS,A. 2003. Are certain habitatsbetter every year? ron lugar durante el periodo de cortejo. Con base en A review and a casestudy on birds of prey. Ecography nuestros resultados,sugerimos que los censosrealizados 26:545-552. para esta especiea lo largo de carreterasson m/rsefec- MEUNIER,ED., C. VEREYDEN,AND P. JOUVENTIN. 2000. Use tivos durante el perlodo reproductivoqueen otras •po- of roadside by diurnal raptors in - cas, cuando los individuos realizan vuelos elevados con scapes.Biol. Conserv.92:291-298. menor frecuencia. Finalmente, la presenciay la distri- MII.I.SAP,B.A. ANDM.N. LEFRANC,JR. 1988. Road transect buci6n de B. lruteodentro del parque no se asociaroncon countsfor raptors:how reliable are they?J.Raptor Res. el tipo de cobertura del suelo. 22:8-16. [Traducci6n del equipo editorial] NEWTON,I., P.E. DAVIES,AND D. MOSS.1994. Philopatry and population growth of Red Kites, (Milvus milvus), ACKNOWLEDGMENTS in . Proc. R. Soc. Lond. B 257:317-323. We are indebted to Pollino National Park, which pro- PENTER•ANI,V. AND B. FAWRE.1997. Breeding density and vided supportfor this project.We are grateful to P. Perna landscape-levelhabitat selectionof Common Buzzard for GIS analysisand to A. Aradis, B. Carelli, E. Giardi- (Buteobuteo) in a mountain area (Abruzzo Appenni- nazzo, N. Pantone, L. Paternostro, R. Rotondaro, P. Sto- nes, Italy). J. RaptorRes. 31:208-212. rino, and S. Urso for their help in the field data record- ing. We thank N.E. Seavy,F. Sergio, and G. Boano for PICOZZI,N. ANDD.N. WEIR.1976. Dispersal and causesof their commentson an early draft of the paper. death in buzzards. Br. Birds 69:193-220. ROBBINS,C.S. 1981. Effect of time of day on bird activity. LITERATURE CITED Pages275-286 in cJ. Ralph and J.M. Scott lEDs.], ANDERSEN,D.E., OJ. RONGSTAD,AND W.R. MITTON. 1985. Estimating numbers of terrestrial birds. Stud. Arian Line transect analysis of raptor abundance along Biol. 6. roads. Wildl. Soc. Bull. 13:533-539. SANCHEZ-Z•tPATA,J.A. AND J.F. C•vo. 1999. Raptor distri- BUSTAMANTE,J. ANDJ. SEOANE.2004. Predicting the dis- bution in relation to landscapecomposition in sem•- tribution of four speciesof raptors (Aves:) arid Mediterranean habitats.J. Appl.Ecol. 36:254-262 in southern :statistical models work better than SERGIO, F., A. BOTO, C. SCANDOLARA,AND G. BOGLIANI. existingmaps. J. Biogeogz31:295-306. 2002. Density, nest-sites,diet, and productivity of CamTER,I. 2001. The . Arlequin Press,Chelms- Common Buzzards (Buteobuteo) in the Italian pre- ford, Essex,England. .J. RaptorRes. 36: 24-32. CAUGI-ILE¾,G. ANDA.R.E. SINCLMR.1994. Wildlife ecology --, C. SCANDOLARA,L. M•RCHESI, P. PEDRINI, AND V. and management. Blackwell Science, Cambridge, PENTERIANI.2005. Effect of agro-forestry and land- England. scapechanges on Common Buzzards(Buteo buteo) in CR•MP, S. ^ND K.E.L. SIMMONS [EDS.]. 1980. Handbook the Alps: implicationsfor conservation.Anim. Conserv. of the birds of , the , and North 7:17-25. . The birds of the western palearctic. Vol. II. SIEGEL,S. ANDNJ. CASTELEAN,JR. 1988. Nonparametric Hawks to Bustards.Oxford University Press,Oxford, Statistics for the Behavioral Sciences. McGraw-Hill, England. Inc., New York, NY U.S.A. (Italian translation.) ELLIS,D.H., R.L. GLINSKI,AND D.G. SMITH.1990. Raptor SPSSINC. 2000. SPSS10.0 for Windows:base, profession- road survey in . J. RaptorRes. 24:98- al statisticsand advancedstatistics. SPSS Inc., Chicago, 106. IL U.S.A. FERRER,M. 1993. Juvenile dispersalbehavior and natal TUBBS,C.R. 1974. The Buzzard. David & Charles, Lon- philopatry of a long lived raptor, the SpanishImperial don, England. Eagle. Ibis 134:128-133. TRACK,AJ., S.S. WALLS,AND R.E. IimNWA•D.1998. Behav- FIELD,A. 2000. Discoveringstatistics using SPSSfor Win- ior in the post-nestlingdependence period of radio- dows. SAGE Publications,London, England. tagged Common Buzzards (Buteobuteo). Ibis 140:58- FULLER,M.R. ANDJ.A.MOSHER. 1987. Raptor survey tech- 63. niques.Pages 37-65 in B.A. Pendleton,B.A. Millsap, VII•UELA,J. 1997. Road transectsas a large-scalemethod K.W. Cline and D.M. Bird [EDS.], Raptor manage- for raptors: the case of the Red Kite (Milvus milvus) ment techniques manual. Nat. Wildl. Fed., Washing- in Spain. Bird Study44:155-165. ton, DC U.S.A. WALLS, S.S. AND R.E. KENWARD. 1998. Movements of ra- GEOMEDIA PROFESSIONAL. 2002. Geomedia Professional dio-taggedbuzzards (Buteobuteo) in early life. Ibis 140' 5.0 for Windows. Intergraph Corporation, Huntsville, 561-568. AL U.S.A. I/mf•GER,O. 2002. Analysisof nest occupancyand nest Received7 October2004; accepted5 September2005 reproduction in two sympatricraptors: Common Buz- AssociateEditor: Fabrizio Sergio