j. Field Ornithol., 66(2):310-319

RECENT LITERATURE

Edited by Robert C. Beason

RESEARCH TECHNIQUES 1. Nightlightingminimizes investigator disturbance in bird colonies.T. D. Bowman,S. P. Thompson,C. A. Janik, and L.J. Dubuc. 1994. Colon. Waterbirds17:78-82.--Investigator disturbancehas been linked to reduced reproductive successin a variety of colonial water- birds. This paper containsa report on nightlighting as a meansof reducing some aspectsof investigatordisturbance. This studywas conducted on Anaho Island, a refuge in Pyramid Lake, WashoeCount, Nevada.Crews of 3-6 with handheld 6V halogen spotlights,banded 1270 birdsfrom 1988-1992. Flightlessyoung of AmericanWhite Pelicans(Pelecanus erythro- rynchos),Double-crested Cormorants (Phalacrocoraxauritus), and California Gulls (Larus californicus)were easilycaught. Adult pelicansand cormorantsflushed from nestsbut re- turned within an hour of investigatordeparture. Gulls flushed but returned to nestsin minutes, and no predation or cannibalismwas observed.Gull chicksremained at or near nestsand hence were not attacked by adult gulls. The authors reported low incidence of dead banded chicks during return visitsafter fledging, and concluded that banded chick mortalitywas low, and that there wasno evidencethat chicksurvival was adversely influenced by capture and banding. The authors emphasizethe importance of scoutingcolonies at a distancebefore nightlightingtrips to help minimize disturbance.Nightlighting was also use- ful for censusingspecies that are difficult to detect, e.g., Black-crownedNight Herons (Nyc- ticoraxnycticorax). Nightlighting advantagesover daytimevisits include reducing or elimi- nating gull predation and reducingthermal stresson eggsand chicks.[U.S. Fish and Wildlife Service,Stillwater National Wildlife Refuge, P.O. Box 1236, Fallon, NV 89406, USA.]--Wil- liam E. Davis,Jr.

BEHAVIOR

(see also 11) 2. Experimental and natural changesin the peacock's(Pavo cristatus)train can affect mating success.M. Petrie and T. Halliday. 1994. Behav.Ecol. Sociobiol.35:213-217.--In a previousstudy, Petrie demonstrateda correlation betweenthe degree of elaborationof pea- cock'strains and their mating successand also showedthat females selectivelymated with maleswith the most elaborate trains. This suggeststhat female choice is responsiblefor mating patterns on the lek but doesnot necessarilyprovide conclusiveevidence that elabo- rate male trains are the only or even the main cue that females respond to. In order to determine more preciselythe importance of a male peacock'strain morphologyin deter- mining its reproductivesuccess, the authors conducted an experiment by removing 20 of the eyespotsfrom 11 wild malesand comparedtheir subsequentmating successto a control group of males.The authorshad alreadydetermined beforehand that the number of spots on a male's train is significantlypositively correlated with the number of copulationsit achieves(P < 0.015). The resultsof the experiment indeed demonstratedthat there was a significantdecline in mating successof individualsin the experimentalgroup comparedto the controlgroup (P = 0.0347). Moreover,the authorsfound that if the relativenumber of eye-spotson an individual changesnaturally with respectto the number of eye-spotsin the trains of other males at a lek site, then the relative number of copulationsthat male obtains tends to changein the samedirection (although not significantly;P = 0.054). These data seem to reaffirm the idea that variation in male peacock train morphology affects their mating success,and that female choice is the driving mechanismthat resultsin nonrandom male mating success.[Dept. of Zoology,South ParksRoad, Oxford, OX1 3PS, UK.]--Danny J. Ingold.

FOOD AND FEEDING

(see also 23) 3. Great Horned Owl food habits at Mono Lake, California. P. A. Aigner, M. L. Mor- rison, L. S. Hall, and W. M. Block. 1994. Southwest. Nat. 39:280-288.--The contents of over

310 Vol.66, No. 2 RecentLite•wture [311

400 Great Horned Owl (Bubo vir•nianus) pellets collected in 1990 and 1991 from two islandsof Mono Lake, California (Paohaand Negit) were analyzedto establishbaseline data on the island fauna. Mammalscomprised the majority of remains identified ti-om pellets taken from both islands(74% on Paohaand 84% on Negit), and rodentswere the most frequentlyoccurring of these (about 70% on both islands).About two-thirdsof the prey remainson Paohawere from deer •nice (Peromyscusma,ziculatus) while about one-third were from montane voles (Microtus montanus). Conversel?;on Negit, x4rtuallyall rodent remainswere from deer mice with only a tiny percentageof vole remains(0.7%). On both islands,birds comprised the secondlargest group of prey ite•ns (16.4% on Paohaand 10.3% on Negit), and CaliforniaGull (Larus californicus)remains were the mostprevelant at both locations.Insects, scorpions, and other arthropodswere only rarely detected in the pellets. Between-islanddifferences in prey re•nainslargely reflect differencesin the thuna on the two islands. Deer mice have been recorded on both islands, but voles have never been re- corded on Negit. The data seemto reflect similar trendsin Great Horned Owl feeding habits at other cold-desertlocations in the southwesternU.S., to the extent that voles,where pres- ent, are consumedfrequently. Conversely, the rate of mouseand bird consumptionon these islandsis •nuch greater than reported fbr other Great Basinlocations. The higher bird con- sumption rate is likely the result of large numbers of nesting gulls in the area. [Dept. of Environ. Science,Policy, and Manage.,Unix,. of Califbrnia, Berkeley,CA 94720, USA.]-- DannyJ. Ingold. 4. Foragingbehavior of White-facedIbises (Piegaffs chihi). J. A. A•nat and F. D. Rilla. 1994. Colon. Waterbirds 17:42-49.--In this stud)' the authors examine the interactions among habitat, flock size,and sex as thesefactors influence the foraging behaviorof White- faced Ibises in grasslandsand wetlands in SE Uruguay in 1991. Data recorded included habitat type, sex, group size,prey captures,periods of vigilance,and agonisticencounters. Solitaryibises were encounteredmore f?equentlyin wetlandsand det•nded feedingterritory vigorously.Females were proportionallymore abundantin grasslands.Ibises f•raged in more denselypacked flocks in wetlandsand fighting and supplantingattacks were more common in wetlandsthan in grasslands.Males, which are larger and have longer bills, were more aggressive,particularly in wetlands.Solitary ibises assumed alert posturemore frequentlythan birds in groups.Prey capture rates increasedwith group size in wetlands,and in groupsup to 6-10, but lessthereafter, in grasslands.Higher capturerates and larger prey suggestthat wetlandsare a better foraging habitat. The authors suggestthat larger flocks in grasslands may have lower capture rates becauseof prey disturbance(withdrawal into burrows), and that the higher proportionof femalesin grasslandsmay be relatedto conspecificaggression, especiallyfrom males. [Estaci6n Bio16gicade Dofiana, C. S. I. C., Apartado 1056, E-41013 Sevilla,Spain.] William E. Davis,Jr. 5. Feeding ecologyof Trumpeter Swansbreeding in South Central Alaska. T. Grant, P. Henson,and J. Cooper.1994. j. Wildl. Manage.58:774-780.--Spring and summerfoods of Trumpeter Swans(Cygnus tmccinator) were examined in order to better understandfhctors that affectTrumpeter Swanhabitat use and breedingsuccess. Data are reportedfi*om 7574 feeding observationsfrom 5 pairs and 4 broodsin 1988 and 3 pairs and 1 brood in 1989. Before and during egg laying,adults foraged primarily on submergedaquatic macrophytes. During incubation, the percent time adults spent feeding on submergedaquatics declined as they began feeding on emergent vegetation.Horsetail (Equisetumfiuviatile and E. arvense) was the first to appear and was the most common food observedin the incubation diet. Males spentmore time feeding on submergedaquatics and lesstime on horsetailthan did femalesduring incubationand post-hatch.During the post-hatchperiod, adultsand young spent more time feeding on horsetailthan all other foods combined.Cygnets fed on the fruiting bodies,young aerial shoots,and aerial shootsand aerial whorlsof the horsetailwhile adultsconsumed the distalportion of the plant. Cygnetsspent less than 2% of their feeding actix4tyon material.Invertebrates were eaten during the first few daysafter hatch, usuallyin conjunctionwith treading beha•4orby adults.Cygnets spent less time feeding on submergedaquatics and more time dabblingthan aduhs.The authorsconclude that wetlands dominatedby horsetail,sedge (Carex lyngbyaei) and submergedaquatics provide the neces- saryfood resourcesfor rapid prefiedglingcygnet growth. Wetlands dominated by pond lily 312] RecentLiterature J.Field Ornithol. Spring 1995

( Nuphar polysepalum),mare's tail ( Hippuris vulgaris),and buckbean( Menyanthestrifoliata) appear to be poorer in qualityand may not provide the adequatefood resourcesfor cygnet recruitment. The authors recommend further researchon cygnet food preferencesand fledging success.Once this is determined,wetlands can be managedto provide the compositionnecessary for cygnetgrowth and survival.[Dept. of Fisheriesand Wildlife, Univ. of Minnesota,Zoo Hodson Hall, St. Paul, MN 55108, USA.]--Robin J. Densmore. 6. Barn owl prey in southernLa Pampa,. S. Tirant. 1992.J. Raptor Research 26:89-92.--Barn Owls (Tytoalba) in La Pampa,Argentina inhabit calden(Prosopis caldenia) forests,Monte Desert shrublandsand agricultural habitats. Pelletswere collected in 1986 and 1988 from two studyareas characterized by all three habitat types.Ninety-six pellets were collectedfrom the first studysite and 110 from the second.Barn owlspreyed largely on cricetid .Pellet analysisrevealed that primary prey speciesin the first studyarea includedAkodon azarae, Calomys sp., and Elig•modontiatypus, found in nearlyequal propor- tions. Calomyssp. (52.1%) and E. typus(25.7%) were prevalentin the secondstudy area. Barn owlsin La Pampapreferred smallerprey species.Geographic variation in Barn Owl diets and prey vulnerabilityare discussed.[Museo Provincialde CienciasNaturales y Antro- pologicas,Pellegrini 180, 1600 SantaRosa, La Pampa,Argentina.]--Robin J. Densmore. 7. Factorsaffecting the use of a freshwaterand an estuarineforaging site by egrets and ibisesduring the breedingseason in New York City. A.D. Maccaroneand K. C. Parsons. 1994. Colon. Waterbirds17:60-68.--In this paper the authors report on a 1988 foraging ecologystudy of Great Egrets (Casmerodiusallms), Snowy Egrets (Egrettathula), and Glossy Ibises(Plegadis falcinellus) at GoethalsBridge Pond (GBP), a freshwaterpond not affected by tides, and RahwayRiver (RR), a tidally-influencedestuarine wetland, which are prime foraging areasfor birds from three local breeding colonies.Based on the numbers of each speciespresent in the breeding colonies,at GBP Great and Snowyegrets were significantly more abundant than expected,and GlossyIbises less. Snowy egrets were more abundant than expectedat GBP during medium and high fidesand lower than expectedat low fide, suggestingthat higher water levels during medium and high tides made foraging at RR difficult. More GlossyIbises foraged at GBP at high tide, again suggestingthat high water levelsat RR drove birds to nontidal GBP. The water level at GBP fluctuated through the breedingseason and the numbersof GlossyIbises and SnowyEgrets were inverselycorrelated to waterdepth. Great Egretswere not as affectedby tidal changesat RR, or water depth at GBP,possibly because they can forage successfullyin deeper water.All three specieswere more abundantthan expectedat GBP during early morning, possiblybecause low-oxygen water drove prey fish to the surface.At RR SnowyEgrets were presentin expectednumbers, but Great Egretswere lower.At low tide SnowyEgrets and GlossyIbises were more abundant at RR than expected.Snowy Egrets had higher strikingsuccess and capturerates at GBP,but inter- and intraspecificaggression at GBP may have limited its use, and mummichogs,the dominant prey items,averaged smaller at GBP. The authorsdo a nicejob of evaluatingthe different factorsthat influence foragingbe- havior in this near-urbanenvironment. [BiologyDept., Friends Univ., Wichita, KS 67213, USA.] --William E. Davis,Jr.

SONGS AND VOCALIZATIONS 8. A study on songmimicry by the Redstart (Phoenicurusphoenicurus) in the Fontaine- bleau Forest,France. [Le chant imitatif du Rougequeue•h front blanc (Phoenicurusphoeni- curus):une fitude en Forfit de fontainebleau,Seine-et-Marne, France.] J. Comolet-Tirman. 1994. Nos Oiseaux 42:267-277. (French with French, English and German summaries.)-- Thirty-sixmales imitated an averageof 17 species,including some that theywould have heard onlyduring migration.The mostfrequent models were Phylloscopus(17.5% of the imitations) and Parus (10.5%). [11 Rue Colbert, F-78000 Versailles, France.]--Robert C. Beason.

NESTING AND REPRODUCTION (see also 1, 2, 19, 25) 9. Responseof female Great Tits, Parus major, to photoperiodic stimulation and the presenceof a male. P.Jonsson. 1994. Ornis Svecica.4:41-47.--Estradiol concentrationand Vol.66, No. '• RecentLiterature [313 ovarian growth in caged and free-living female Great Tits were measured and compared in an attempt to determine the influence of photoperiodicstimuli and male presenceon ovar- ian maturation.Females were separatedinto two groups:Group 1: female/male pairs,with accessto nest-buildingfacilities kept on a long day regimen (20L:4D); Group 2: female/ female pairs, also kept on the long day regimen. A third group consistingof female/female pairswas maintained on short days (8L: 16D). Free-livingfemales served as a reference group. All femalesin the study,both free-lix4ngand caged, had estradiollevels that remained low throughout the experiment, and showedno significantdifference betweengroups. Females from the long day groupswere compared and it was found that those females kept in the presenceof a male showedno difference in estradiolsecretion or follicular growth. It was unknown why sexuallymature males failed to promote the maturation process.However, it was theorized that some unknown environmental factor was missingor the stressimposed on the females depressedgonadotropin secretion.Females kept in the short day regimen failed to demonstrateany ovarian size increase. Long day regimented females exhibited incomplete ovarium and follicle growth. In free-livingfemales, follicle growth occurred at the sametime circulatinglevels of estradiolincreased. The lack of ovariangrowth in captive femalesmay therefore have been the result of insufficientestradiol production. The hyper- stimulationof long day regimented birds is hypothesizedto inhibit gonadal growth. This in turn may have resulted in the males failing to properly stimulate the females at a point critical to follicular development as a result of their own testicular regression.Testing this hypothesiscould be accomplishedby substitutingmales that are in an earlier phase of the sexualcycle. Females from group 1 had significantlysmaller largest follicles than femalesin group 2. Possibleexplanations include the possibilitythat the males in group 1 had an inhibitory effect on the females,or that the female/female pairsresulted in the development of competition between the two individuals,based on the suppositionthat a male would choosethe most mature. [Dept. of Zoology,Medicinaregatan 18, S-413 90 Goteborg, Swe- den.]--Sue Bennett.

10. Orientation and spacingof nestingboxes used by EasternBluebirds and Tree Swal- lows.S. G. Parren. 1994. Sialia 16:127-129.--The generalbelief amongthose who erect nest boxesfor EasternBluebirds (Sialia sialis)is that the cavityentrance should face in a southerly or southeasterlydirection to enhance nesting success.In this study,the author determined that EasternBluebirds did not occupynest boxes that facedin a southerlydirection (90ø to 270ø) in a greaterproportion than expectedby chance(n = 78 occupiedboxes; P = 0.705). Moreover,when the range of directionswas narrowed to 135ø to 150ø, bluebirdsstill did not occupythese boxessignificantly more than boxesfacing in other directions (P = 0.211). A similar trend was detected for Tree Swallows(2hchycineta bicolor) in which boxes facing in a southerlydirection (90 ø to 270ø ) wereoccupied in proportionsabout equal to thoseexpected by chance (P = 0.443). The author suggeststhat nest-boxorientation shouldbe basedlargely on knowledgeregarding the local conditionsand ease of observationrather than simply erecting all boxes in a southerlyor southeasterlydirection. Regarding the spacingof nest boxes,there is widespreadagreement that bluebirdswill not typicallynest closerthan 90 m of each other; Tree Swallows,on the other hand, will tolerate other nesting swallowswithin about 30 m. The author's data generally confirm these observations.Only four boxes oc- cupied by bluebirds were closer than 90 m to other nesting bluebirds, while swallowsfre- quently nested within 30 m of other swallows,as well as bluebirds, about half of the time. However,significantly more bluebirds(18.3%) occupiednest boxeswithin 15 m of nesting Tree Swallowsthan did other nestingswallows (6.5%) (P = 0.047). These data suggestthat pairing nest boxeswithin 15 m should help discourageswallows from occupyingall of the availablenest boxeson a bluebird trail and provide an advantagefor bluebirds.[Nongame and Nat. Heritage Program,Vermont Fish and Wildl. Dept., 103 S. Main Street, Waterbury, VT 05671-0501,USA. ]--Danny J. Ingold. 11. Female reactionsto male absenceafter pairing in the Pied Flycatcher.O. Ratti. 1994. Behav.Ecol. Sociobiol.35:201-203.--In Pied Flycatchers(P•cedula hypoleuca), females that mate with an already-matedmale are at a disadvantagesince such males mainly concen- trate their feeding efforts on the young of the primary brood. Nonetheless,females occa- sionallydo mate with already-matedmales. When this occursand females remain with an 31 4] RecentLiterature J.Field Ornithol. Spring 1995

already-matedmale, it suggeststhat they either have not evolved a responsestrategy to the absenceof males or that they have assessedthat the costsof finding an unmated male are too high. In this study,male Pied Flycatchersin Finland were removedfrom their territories for 60 min to mimic the behavior of polyterritorial males.This allowed the author to inves- tigate the responseof fenhalessoon after settlementto the absenceof their mates.Only 4 of 22 fenhalesabandoned their mates after removal, even though there were availableunmated males nearby.These data seem to be consistentwith a "deception" hypothesissince females did not use occasional•nale absenceas a cue to evaluatethe breeding statusof their mates. [Dept. of Biology,Univ. ofJyvaskyla,Yliopistonkatu 9, FIN-40100Jyvaskyla,Finland. I--Danny J. Ingold. 12. Four youngGolden Eagles(Aquila chrysaetos)reared in the FrenchAlps. [Quatre jeunesd'Aigle royal (Aquila chrysaetos)s'envolent de la m•me aire dansles Alpes fran•aises.] J.-F. Desmet, C. Couloumy,J. Blondel, and C. Lavigne. 1994. Nox Oiseaux 42:305-310. (French with French, English and German summaries.)-•A trio (1 male and 2 fenhales)of Golden Eaglessuccessfully reared 4 young in a single nest. Both bigamyand successfulrear- ing of so many young is exceptional. [GRIFEM Groupe Rech. et Info. sur la Faune et les Ecosyst•mesde Montagne, F-74340 Sam6ens,France. I--Robert C. Beason. 13, Wading bird nesting at Lake Okeechobee,Florida: An historic perspective.P. G. David. 1994. Colon. Waterbirds 17:69-77.--Lake Okeechobeeis managed with a multiple- use strategywhich includescompeting objectives (e.g., flood control, agriculturalwater sup- ply, wildlife resources,and recreation). Controlled water levelsare highestat the beginning of dry season(water supply) and lowestat the beginning of wet season(flood control). This paper containsa historyof wadingbird use at the lake and examinesthe impact of managed water level changeson breeding wading birds. Surveysof breeding colonieswere conducted from 1957-1960, 1971-1976,and intensivelyfrom 1977-1988.Anecdotal reports dating tkom the 1930sdescribe Lake Okeechobee as an important wading bird nesting locality.A critical event occurred in 1978 when a new water regulation schedule increasedwater levels at all seasonsby more than a foot, thus affectingforaging habitat for wading birds, and flooding critical willow tree nestingareas. Preregulation (1957-1978) means,excluding Cattle Egrets (Bubulcusibis), of nearly 5000 breeding pairs fell to a postregulationmean of about 2000 (1978 = 6633 pairs;1988 = 1298). Cattle Egret numbersincreased from 200 pairsin 1957 to 10,400 in 1978, but declined to 4000 in 1988. White Ibises (Eudocimusallms) peaked in 1974 at 10,000 pairs, but declined to 200 in 1988. Great Egrets (Casmerodiusallms) and GlossyIbises (Plegadisfalcinellus)have experiencedsignificant declines. The author suggests that increasedwater levelshave influenced both foragingopportunities and nestingsubstrate. The lossof willowsat a key colonyhas been particularlydamaging. In addition, the increase in Cattle Egret numbers may have affected nesting trees.The author concludesthat future decisionsconcerning water regulation schedulesmust considerthe impact of thesedecisions on wading birds and other wildlife. [Dept. of Research,South Florida Water Management District, P.O. Box 24680, West Palm Beach, FL 33416, USA.]--William E. Davis,Jr. 14. Distribution of the Tengmalm'sOwl (Aegoliusfunereus) in natural cavitiesin the Jura vaudois. [Rfipartition de la chouette de Tengmalm (Aegoliusfunereus) dans les sites natureIsduJura vaudois(Suisse).] P.-A. Ravussin, P. Walder, P. Henrioux, V. Chabloz,and Y. Men,trey. 1994. Nox Oiseaux 49:245-260. (French with French, English and German sum- maries.)--In the Jural mountains, 160 of 161 nestslocated were between 1040-1390 m ele- vation. Most (98.1%) of the cavitieswere excavatedby Black Woodpeckers(Dryocopus mar- tius) in large beeches(Fagus sylvatica). The cavityopenings averaged 48.9 cm in diameter and were a mean of 9.1 m high, with 85% above7 m. [CH-1446 Baulmes,Switzerland.]-- Robert C. Beason.

MIGRATION, ORIENTATION, AND HOMING (see 21) HABITAT USE AND TERRITORIALITY (see also 4, 6, 7, 13, 14, 18, 26) 15. New birds on the block: new neighbors increasedefensive costsfor territorial male Willow Ptarmigan.P. Easonand S.J. Hannon. 1994. Behar. Ecol. Sociobiol.34:419-426.-- Vol.66, No. 2 RecentLiterature [ 315

Previousstudies have demonstratedthat there are potentially numerous benefits associated with site fidelity or breeding philopatty in varioustaxa, particularlyin birds and •na•mnals. Among these are increasedfa•niliarity with a territory which •nay facilitatefinding food or avoiding predators,increased fa•niliarity with a •nate, and increasedfa•niliarity with neigh- bors. So•nestudies have shownthat havingfamiliar neighborscan be beneficialby reducing the levelof fightingbetween neighbors, but generallydo not addressthe questionof whether the benefitsof suchfamiliarity persists year after year.The goal of the authorsin this study wasto testthe hypothesisthat defendinga territory againstformer neighborsfrmn a previous year is lesscostly than defendingit againstnew neighbors.To this end, the authorsobserved Willow Ptarmigan (Lagopuslagopus) on the subalpinetundra of Chilkat Passin northwestern British Colu•nbia during the 1991 breeding season.They found that territorial •naleswith new neighborsspent significantly•nore ti•ne in defensecronpared to territorial •naleswith former neighbors (P < 0.01). Moreover, •naleswith severalnew neighbors spent •nore ti•ne defending their territories than •naleswith fewer new neighbors,and maleswith both new and former neighborsspent •nost of their ti•ne fighting with their new neighbors.The in- tensityof fights involvingnew neighborswas also significantlygreater than fights between former neighbors(P < 0.05). Although there appearedto be stoneage differencesin fight- ing behavior (i.e., fights involvingtwo yearlingswere •nore extreme than other fights), the significantdifferences observed in fightsbetween new and former neighborswere not solely the result of the effectsof age on fighting behavior.Based on the resultsof this study,the authorssuggest that the presenceof new neighborsappears to be costlyto •nale ptarmigan, and that the processof fa•niliarizationwith a new neighborlikely resultedin the increased costs.Thus, male ptarmigan•nay be able to alleviatethe costsof establishingand defending a territory through nest-sitefidelity. [Dept. of Zoology,Univ. of Alberta, Ed•nonton,Alberta, T6G 2E9 Canada.]--DannyJ. Ingold.

ECOLOGY

(see also 5, 24)

16. Structure, seasonaldynamics and energeticsof the avifauna in Macedonian oak forest. B. Micevski.1994. Larus 44/45:49-63. Avifaunastructure and dynamicsin the sub- mediterraneanco•mnunity of Macedonianoak (Quercetummacedonicae) forest was investi- gated. Speciesrichness, ho•nogeneity, diversity and do•ninancewere determined, and the energyexpenditure of birdswas calculated by useof Poole's•nodel and Walsberg'sformula. Adult bimnasswas determined by catchingand weighingthe birds,as well asfrown literature. Basedon censusdata, birds were either classifiedas certain breeders,probable breeders,or nonbreedersin the studyarea. Speciescronposition and activitywere found to be cyclicwith the time of year.Avian speciesrichness was found to peak during the springbreeding period, with the low occurringin late autu•nn and winter. Maxi•nu•nhmnogenity was found to occur during the breeding and postbreedingperiod, with •nini•numsin all other periods of the year.Not surprisingly,this finding correspondsto the increasedsociability that occursduring thesenonbreeding portions of the year.The diversityindex (which is actuallya co•nbination of the two previousmeasures) was found to be highest during the spring breeding and postbreedingseasons. The annual •nean avian biomass(for two annual cycles)was calculated to be 2657 g/10 ha, with a correspondingannual averageenergy consu•nptionvalue of 3,444,039kJ/10 ha, or 23% of the ecosyste•nis net pri•nary production.Maxi•nu•n bio•nass value wasfound to occur in the winter when the nu•nber of avian specieswithin the study area was greatest. Breeding birds (28 continned breeding species)were found to have a bio•nassof 2617.7 g/10 ha, with respectto their abundancein the bird cmmnunity.Average dailyenergy expenditure of this groupwas calculated to be 7007.5kJ/10 ha. Latitudewas alsofound to be an i•nportantfactor, as bird co•mnunitydensity in the oak forestwas found to vary (25 pairs/10 ha at 57øNto nearly180 pairs/10 ha at 49øN).A slightdecrease to the S wasnoted frownprevious work by sameauthor in different oak forest.Overall, it wasde- termined that the averageage of the forestand its geographicalposition are very influential in determiningforest bird co•mnunitydensity. [Institute of Biology,Faculty of Science,Skopje 91000, Macedonia.]--Sue Bennett. 316] RecentLiterature j. FieldOrnithol. Spring 1995

17. Avian communitiesof fragmentedsouth-temperate rainforests in Chile. M. F. Will- son, T. L. DeSanto, C. Sabag,andJ. J. Armesto. 1994. Conserv.Biol. 8:508-520. Temperate rainforestsof are vulnerableto the eft•cts of forest fragmentationthat are occurringbecause of increasedlogging, charcoal production, and agriculturalclearing. To examine the relationshipof forestfragment sizeand bird diversity,avifauna were censused with point-countsfrom early November to mid-December,1992, in the Valdivian rainforest on Isla Grande de Chiloe, in south-centralChile. Forestfragments were tiny (<0.5 ha, n = 3), small (2-6 ha, n = 5), or large (>10 ha, n = 3). The diversityand relative abundance of bird speciesdecreased as the size of the habitat patch decreased.Ecological categories, including endemics,mutualists (pollinators or seed dispersers),understory species and spe- cies dependent on large trees,were not differentiallysensitive to patch size. Nevertheless, most of the specieswith significantdeclines were endemic (6/7), coverednesters (6/7), or understorydwellers (5/7). Some mutualistsand big-tree userswere affected, too. These specieslosses will becomemore severeas clearing of the forestcontinues. Possible mitigation measuresinclude leavingsmall standsof forest and corridorsbetween habitat patchesand in certain circumstances,alternative agricultural practices. [Forestry SciencesLaboratory, 2770 SherwoodLane, Juneau, AK 99801, USA.]--Kristin E. Brugger.

POPULATION DYNAMICS

(see also 25) 18. Populationestimates of breedingblackbirds in North Dakota, 1967, 1981-1982 and 1990. C. O. Nelms, W. J. Bleier, D. L. Otis, and G. M. Linz. 1994. Am. Midl. Nat. 132:256- 263.-Breeding populationsof Red-wingedBlackbirds (Agelaius phoeniceus), Yellow-headed Blackbirds (Xanthocephalusxanthocephalus), and Common Grackles ( Quiscalusquiscula) were censusedin 129 quarter-sectionsthroughout North Dakota during 1990.The statewide total of breeding blackbird pairs was estimatedto be 2,302,000 (SE = 335,000), of which 1,143,000were Red-wingedBlackbirds, 768,000 Common Grackles,and 391,000 Yellow-head- ed Blackbirds.The proportion of the sampleunits containingblackbirds declined signifi- cantly acrossyears from 1967 to 1990 (P = 0.0001); moreover, blackbird abundancewas generallydown. Numbers of Red-wingedBlackbirds declined significantly from 1967 to 1981- 1982,and againfrom 1981-1982 to 1990.Yellow-headed Blackbirds in 1990were significantly fewer than in 1981-1982, but no significantdifference was detected between their numbers in 1967 and 1990. Grackleswere significantlymore abundant in 1981-1982 than in 1967, but no difference was detected between 1990 and the two previoussurveys. None of the blackbird speciesused habitat in proportion to its availability.Yellow-headed Blackbirds were most frequentlyobserved in wetlandswhile Red-wingedBlackbirds and Common Grackles were found in most habitats.Nonetheless, about half of the Red-wingedBlackbirds were found in wetlandswhile mostgrackles were locatednear residences.[Dept. of Zoology,North Dakota State Univ., Fargo, ND 58105, USA.]--DannyJ. Ingold.

ZOOGEOGRAPHY AND DISTRIBUTION

19. Nesting, behavior,distribution, and speciationof Patagonianand Andean Ground Tyrants (Myiotheretes,Xolmis, Neoxolmis,Agriornis, and Muscisaxicola).F. Vuilleumier. 1994. OrnitologiaNeotropical 5:l-55.---The life historycharacteristics of six speciesof brush and ground tyrantsare discussed:four Patagonian (Xolmispyrope, Neoxolmis rubetra, Neoxolmis ruffrent,isand Muscisaxicolacapistrata) and two Andean species(Myiotheretes rufipennis and Agriornisandicola). In this paper the author presentsthe resultsof his own investigations and thoseof other researcherson thesespecies. Because these species are shy and elusive, little is known about them. The known information is summarizedfor each speciesand discussedin comparisonwith their congeners.[Dept. of Ornithology,American Museum of Natural History, Central Park West at 79th St., New York, NY 10024, USA.]--Robert C. Bea- son.

20. Observationson MountainPlover (Charadriummontanus) breeding in Utah. K. S. Day. 1994. Southwest.Nat. 39:298-300.---•though Mountain Plovershave been reported in Utah since1915 (consideredrare transientsor casualmigrants), breeding plovers have never Vol.66, No. • RecentLiterature [ 317

been documentedin the state.During the 1993 breedingseason, the author reportsfinding three Mountain Plover nestswith broodsamong the Pariette Bench oil and gasproducing fieldsin DuchesneCounty about 13 km southof Myton. Adult ploverswere first reported in late April by which time theywere incubatingeggs; two of the nestswere locatedin flat areas with sparselow-growing grasses while the third wasfound in moderatelydense black sage- brush (Artemesianova). The author estimateshaving observed a total of 31 ploversaround the three nest locationsin 1993:9 adults,15 chicksin 8 broods,and 7 of undeterminedage. Ploverswere last observedon 26 July. [Utah Divisionof Wildl. Resources,152 E. 100 N., Vernal, UT 84078, USA.]--DannyJ. Ingold.

SYSTEMATICS AND PALEONTOLOGY

(see 19)

EVOLUTION AND GENETICS

(see 2)

PHYSIOLOGY AND DEVELOPMENT

(see 9)

PLUMAGES AND MOLTS

21. Moult in relation to migration in birds--a review. N. Kjellen. 1994. Ornis Svecica 4:l-24.--The relationshipbetween moult and migrationduring a yearlycycle was examined. Three groups of birds were defined (raptors,waders and warblers) with variousgenera, speciesand populationsof each being comparedto determine which of six previouslyde- fined moult strategieswas utilized. In addition,migratory distance was analyzed to determine the influence its potential influence on the moult strategyemployed. Among raptors, short distancemigrants were discoveredto undertakethe majorityof their moult on the breeding grounds.Medium distancemigratory raptors moulted in both summerand winter quarters, while thoseraptors that migratelong distancesundertook the majorityof their moult in their winter quarters.Wading birds differed in that migrantswere found to exhibit a more rapid moult when comparedto residentpopulations, with the latter generallyexhibiting a tendency to spreadtheir moult overas long a period of time aspossible. Moult durationand individual variation among waderswas found to increasewith decreasinglatitude, possiblydue to in- creasedfood sourceavailability or stability.However, moult among wadersmay ultimately depend on the commencementof breeding. Relativelyfew wadersmoult on the breeding grounds.Instead, they moult at stop-overor winteringsites. Six generaof Palearcticwarblers were alsoexamined and found to exhibit fairly diversemoult strategies.Most Sylvidaedem- onstratea completesummer moult, regardlessof migratorydistance traveled. However, some speciesexhibit different strategies, including winter moult, suspended moult at variousstages, and a split moult, which is postulatedto be a compromisebetween complete summer and winter moult strategies.The author concludesthat migratorydistance appears to influence the particular moult strategyundertaken; however,within species,different populationsmay demonstratedifferent moulting strategies.[Dept. of Ecology,Animal Ecology,Univ. of Lurid, EcologyBuilding S-223,62 Lund, Sweden.]--Sue Bennett.

PARASITES AND DISEASES

22. Mercury and cause of death of Great White Herons. M. Spaldina, R. Bjork, G. Powell,and S. Sundlof.1994. J. Wildl. Manage.58:735-739.--Mercury contamination was studied in Great White Herons (Ardea herodiasoccidentalis) as part of a studyof effectsof diseasesand contaminantson reproductivesuccess of wadingbirds in southernFlorida. Sixty- four nestlingand 23 adult heronswere radio-taggedbetween March 1987 andJune 1989. Twenty-twocarcasses were recoveredand analyzed.Birds were categorizedbased on suspect- ed causesof death. Category A birds died acutely from known or presumed causes (poisoning,collision, etc.), and categoryC birds died from one or more chronic diseases. CategoryA birdshad lowerliver mercuryconcentrations than did categoryC birds.Juveniles that had dispersedto the mainland had higher mercury concentrationsthan did those that 318] RecentLiterature J.Field Ornithol. Spring 1995

did not migrate. More than one diseasewas most often the causeof death; these diseases includedeustrongTlidosis (4 birds), pyelonephritis(3), gout (3), severeintestinal parasitism (3), myopathy(2), and septicemia(2). The authors concludedthat although mercury con- tamination is detrimental to the health of birds, it is more detrimental to their reproductive success,which can severelyimpact populationdemographics. They suggestthat further mon- itoring of mercury contaminationis necessaryand more researchis needed to determine the source of mercury in the aquatic food chain. [Dept. of Infectious Diseases,College of Vet. Medicine, Univ. of Florida, Gainesville,FL 32611, USA.] --Robin J. Densmore.

WILDLIFE MANAGEMENT AND ENVIRONMENTAL QUALITY (see also 10, 12, 13, 17, 22) 23. Wadingbird use of wastewatertreatment wetlands in centralFlorida. P. C. Frederick and S. M. McGehee. 1994. Colon. Waterbirds 17:50-59.--The use of wastewater treatment wetlands (treated urban sewage),either as newly created or converted natural wetlandsis likely to increaseas human population densityincreases. These wetlandsare potentiallyuse- ful to long-leggedwading birds as foraging and breeding sites.This study evaluated the use of Iron Bridge and Mulberry wastewatertreatment sitesin central Florida by Ciconiiformes for foraging and breeding, and compared their use to the St. Johns river marshesadjacent to the Iron Bridge site and to other natural wetlandsin Florida and Nicaragua.Densities of birdswere estimatedfrom aerial surveysduring October and December 1991, and February- May 1992, and breeding colonieswere surveyedfrom March-May. Densitiesincreased from October-February and then decreased.The St. Johns marsheshad the highest densitiesof White Ibises(Eudocimus allms), Glossy Ibises (Plegadisfalcinellus), and Wood Storks(Mycteria americana),presumably because the higher water levelsof the treatmentsites were lesssuit- able for tactile feeders.The densitiesof SnowyEgrets (Egrettathula) and Great Egrets (Cas- merodiusallms) were similar in the three sites.All three siteshad higher densitiesof waders than other natural sites in S Florida and Nicaragua. Both wastewatersites had breeding colonies,and many Snowyand Great Egrets,followed to foraging sitesin fixed-wingaircraft, landed within the wastewater sites. Most birds from colonies outside the treatment sites for- aged elsewhere.Although treatment sitesare utilized for breeding coloniesby herons and ibises,and for foragingby herons, the potential effectsof accumulatedcontaminants, and the nematode parasiteEustrongylides ignotus, which is found at siteswith elevatednutrients, have not been well researchedand posepotential hazardsto wading birds. [Dept. of Wildlife and Range Sciences,118 Newins-ZieglerHall, Univ. of Florida, Gainesville,FL 32611, USA.]-- William E. Davis,Jr. 24. Sustainableuse of the tropicalrain forest: evidencefrom the avifaunain a shifting- cultivationhabitat mosaicin the ColombianAmazon. G. I. Andrade and H. Rubio-Torgler. 1994. Conserv.Biol. 8:545-554.--In a 1-yearstudy located in the terra firme forest at the Miriti-Paranariver, the avifaunaof regeneratingcrop fields (1-ha in size, 1-17 yearsafter cultivation ceased) was compared to that of undisturbed understory sites. Few differences were observedin speciesrichness or number of individualscaptured in mist nets. However, the avifaunaof old fields (13-17 yr since cultivation) was most similar to forest understory and avifaunaof young fields (<10 yr) was least similar.The authors suggestthat slashand burn agriculture is a high-intensity,low magnitude disturbance,with disturbanceeffects last- ing about 10 years.This type of agriculture may mimic natural gap-phasedynamics, thus offering an example of a potentiallysustainable use of tropical forests,from a standpointof bird community management. [Fundacion Natura Colombia, A. A. 55402, Santafede Bogota, D.C., Colombia.]--Kristin E. Brugger. 25. Decline of the Red-cockadedWoodpecker (Picoidesborealis) in southeasternOkla- homa. J. E Kelly, S. M. Pletschet,and D. M. Leslie,Jr. 1994. Am. Midi. Nat. 132:275-283.- The 4600 ha McCurtain County WildernessArea (MCWA), Oklahoma, wassurveyed during the 1989-1990 breedingseasons for Red-cockadedWoodpeckers in order to detect a poten- tial population decline since a similar censuswas conducted in 1977. Since hardwoodscur- rently compriseabout 40% of the basalarea on the MCWA, the authorsalso quantified foraginghabitat variablesand comparedthe spatialrelationship among colonysites between xro•.66, No. 2 RecentLiteratu•v [319

1977 and 1990. Eleven groupsof Red-cockadedWoodpeckers used clustersof cavitytrees within the 3795 ha where 29 active clans were found in 1977, a 62% decline. A total of 31 individualswere located on the MCWA in 1990, 22 of which were located on the resurveyed area, representinga 75% declinesince 1977. A total of 35 activecavities were found, but 9 were abandoned dt•ring the study.Nests were located in 5 of 6 active clustersin 1989 and in 8 of 15 activeclusters in 1990. All 13 of thesenests produced nestlings but only 9 indi- vidualsultimately fledged (0.69 fledglings/nest).Differences in the habitatstructure of high versuslow densitywoodpecker groups were minimal.However, values for pinestended to be at the low end and valuesfor hardwoodstended to be at the high end of acceptableranges recommendedin the Red-cockadedWoodpecker Recovery Plan (USFWS, 1985). Nearest neighbor differencesbetween clusters were significantlylonger in 1977 comparedto 1990. The productivityof Red-cockadedWoodpeckers on the MCWA in 1989 and 1990 was less than half of that for woodpeckersin SouthCarolina, North Carolina,and Florida.The data in this studyshow that numbersof Red-cockadedWoodpeckers declined despite being sur- rounded by fora•ng habitat that meets the RecoveryPlan's recommendations. The authors suggestthat these recommendationsmay thus be inadequate and that management tech- niquesformulated for woodpeckersin secondary-growthforests may not sufficefor wood- peckersthat inhabit old-growthforests. [Oklahoma Coop. Fish & Wildl. ResearchUnit, U.S. National BiologicalSurvey, Dept. of Zoolo•; Oklahoma State Unix,.,Stillwater, OK 74078, USA.]--Danny J. Ingold. 26. Effect of white-tailed deer on songbirdswithin managed foresCsin Pennsylvania. D. de Calesta.1994. J. Wildl. Manage.58:711-718.---The effect of white-taileddeer (Odocoi- leusvirginianus) on speciesrichness and abundanceof songbirdswas examined in north- western Pennsylvania.Data were collected in and around Allegheny National Forest fi•om 1980-1990. Four 65-ha study siteseach contained four deer enclosuresof 1 deer/26-ha, 1 deer/13-ha, 2 deer/13-ha, and 4 deer/13-ha, simulating deer densitiesof 4, 8, 16 and 31/ km2 respectively.Each enclosure was subdivided into three silviculturaltreatments (clear-cut, thinned, and uncut). Point countsof birdswere conducted5 timesper site from mid-May throughJuly, 1991. Forty-eightspecies of songbirds(range 31 to 43) and 2912 individual songbirds(658-789/site) were recordedamong the four sites.Percent ground cover was not affected by deer; however,increasing deer densitieswere associatedwith decreasesin flow- ering plantsand increasesin ferns and grasses.Mean saplingheight was reduced by deer on all treatmentsites. Varying deer densityhad no effect on ground-or upper canopy-nesting songbirds,but speciesrichness and abundanceof intermediatecanopy-nesting (ICN) song- birdsdeclined 27% to 37% respectivelybetween lowest and highestdeer densities.Four ICN specieswere not observedat deer densitiesgreater than 7.9/km2 and two ICN specieswere not observedat densitiesgreater than 14.9/km• In order to protect and maintain forest songbird populations,deer densitiesshould be maintained at around 8/kin' in intensely managedforests to lessthan or equal to 4/km'-' in lessintensely managed forests. [U.S.ES., NortheasternForest Experiment Station,P.O. Box 928, Warren, PA 16365, USA.]--RobinJ. Densmore.