THE RAPTOR RESEARCH FOUNDATION, INC. (Founded 1966) http://biology.boisestate.edu/raptor/ OFFICERS SECRETARY: Judith Hfnckel TREASURER: Jim Fitzpatrick BOARD OF DIRECTORS INTERNATIONA!. DIRECTOR #3: S i eve Re.dpath DIRECTOR AT LARGE #1: Jemima ParryJones DIRECTOR AT LARGE #2: Eduardo Inigo-Elias DIRECTOR AT LARGE #3: Michael W. Collopy DIRECTOR AT I.ARGE #4: Carol McIntyre DIRECTOR AT LARGE #5: John A. Smallwood DIRECTOR AT LARGE #6: Daniel E. Varland Ruth Tingay NORTH AMERICAN DIRECTOR #I : Steve Hoffman NORTH AMERICAN DIRECTOR #2: Gary Santolo NORTH AMERICAN DIRECTOR #.3: Ted Swem INTERNATIONAL DIRECTOR #I : Nick Mooney INTERNATIONAL DIRECTOR #2: PRESIDENT: Brian A. Millsap VICE-PRESIDENT: David M. Bird ^ 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 ( 8 V 2 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 numer- als. 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 J. Raptor Res. 39(1):1-10 © 2005 The Raptor Research Foundation, Inc. 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 tem- perature (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 esta- ban 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 precipi- tacion 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: john.elliott@ec.gc.ca 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 com- ponente mas importante en la costa oeste (Scomber japonicus = 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 productivity in natural ecosystems (Newton 1979, 1998), including Bald Eagles (Haliaeetus leucoce- phalus-, Hansen 1987, Dykstra et al. 1998), White- tailed Sea Eagles {Haliaeetus albicilla; Helander 1985), African Fish-Eagles {Haliaeetus vocifer, Harp- er et al. 2002), Wedge-tailed Eagles {Aquila audaxr, Ridpath and Brooker 1986), Golden Eagles {Aquila chrysaetos; Watson et al. 1992), and Ospreys {Pan- dton haliaetus] van Daele and van Daele 1982), among others (Platt 1976, Dykstra et al. 2003, Hak- karainen et al. 2003). Although some Bald Eagle populations are still at least partly influenced by toxic contamination (Anthony et al. 1993, 1994, 1999, Kumar et al. 2002, Bowerman et al. 2003, Dominguez et al. 2003), several populations now appear to be regulated by natural agents, primarily food abundance (e.g., Dzus and Gerrard 1993, Donaldson et al. 1999, Anthony 2001, Stout and Trust 2002, Gill and Elliott 2003). Landscape features, especially tidal flats, influ- ence eagle-prey availability, and therefore, produc- tivity (Hansen 1987, Watson et al. 1991, Dzus and Gerrard 1993, Gende et al. 1997, Wilson and Arm- strong 1998, Watson 2002). Weather also influenc- es raptor reproductive success, either by affecting adult or chick energetic needs (Newton 1978, 1998, Stalmaster and Gessaman 1984), prey avail- ability (Seavy et al. 1998, Panasci and Whitacre 2000, Harper et al. 2002, Jaksic et al. 1997), or adult foraging effectiveness (Grubb 1977, Newton 1978, Stinson 1980, Gilchrist and Gaston 1997, Gilchrist et al. 1998, Fritz 1998). Whereas rainfall usually increases foraging success for tropical rap- tors, due to increased productivity at lower trophic levels during the rainy season and decreased heat stress in canopy nesters (Seavy et al. 1998, Panasci and Whitacre 2000, Harper et al. 2002, Jaksic et al. 1997, Touchton et al. 2002), rainfall usually reduc- es prey availability, increases chick energetic needs, and adult-nest attendance in temperate . regions (Newton 1978, 1998, Kruger and Lindstrom 2001, McDonald et al. 2004). For example, rain reduced the ability of Ospreys to locate prey by increasing the number of ripples on the water surface (Grubb 1977). In addition, the number of rainy days dur- ing early spring was negatively correlated with Bald Eagle productivity in southeastern Alaska (Gende et al. 1997), but not in the drier interior regions of Alaska (Steidl et al. 1997). In this study, we investigated the factors influ- encing provisioning rates at Bald Eagle nests along the Vancouver Island shoreline in coastal British Columbia. Elliott et al. (1998) and Gill and Elliott (2003) showed that eagles nesting on the west coast had lower productivity than those nesting on the east coast, and conjectured that this was due to wetter springs and fewer tidal flats limiting the amount of food brought to nests. We therefore hy- pothesized that (1) provisioning rates would be negatively correlated with tide height and (2) pro- visioning rates would be lower during periods of rain. Previous investigators (Gerrard et al. 1979, Bor- tolotti 1984a, Jenkins 1989, Kennedy and Mc- Taggart-Cowan 1998, Warnke et al. 2002) have de- scribed Bald Eagle nesting behavior using direct observation and time-lapse photography. Warnke et al. (2002) established several benchmarks for the nest provisioning and chick behavior of an in- land population that did not seem to be limited by food. In this paper, we used both methods to com- pare the behavior of eagles from coastal Vancouver Island with those presented by Warnke et al. (2002) for Wisconsin. Study Area and Methods Study Area. During May-July 1996, we monitored Bald Eagle nests on the east (Crofton, 48.9°N, 123.7°W) and west (Barkley Sound, 48.9°N, 125. 3°W) coast of southern Vancouver Island, British Columbia. On the west coast, the marine environment drops off steeply from shore while the sheltered waters on the east coast include large March 2005 Bald Eagle Provisioning Rates 3 tidal flats where many eagles forage. In addition, the ex- posed west coast tends to be cooler and windier, with more storm events, than the protected east coast, and nesting begins ca. 1 mo later (Elliott et al. 1998). Within each study area, we selected nests where placement of video recording equipment afforded a good vantage for nesting observations. Observations. We positioned six (three on each coast) miniature CCD cameras (V-1205, Sony, Vancouver, BC, Canada) 2 m above the nests when nestlings were ca. 4 wk old. Our observations corresponded ca, to the “mid- dle nesting stage” identified by Warnke et al. (2002). Cameras were housed in waterproof compartments, cam- ouflaged using paint and vegetation and connected via power and RG-8UM video lines (RG-8UM, CB World, Lansing, MI U.S.A.) to a DC VCR (Panasonic AG-1070 one frame- s ^ Secaucus, NJ U.S.A.) on the ground. We replaced the videotapes every 3 d. VCRs were housed in waterproof compartments 20 m from the nest tree and programmed to record from 0500-1100 H and 1430- 2030 H (812 hr total footage). Two 12-volt deep-cycle- marine batteries in protective housing supplied power. We analyzed video recordings by viewing on a television monitor. We conducted direct observations using 20-60 X spot- ting scopes from a blind at four nests on the east coast and three on the west coast (^6 d/nest, each 16 contin- uous hours dawn to dusk) for 1344 hr total. Nestlings were 2-10 wk old. Observers worked in pairs 100-300 m from the nest, with individual observers switching every 2 hr (Warnke et al. 2002). To corroborate the compatibility of observation meth- ods, we collected direct observation and video data si- multaneously for 20 hr. As was found by Dykstra et al. (1998) and Warnke et al. (2002), both methods had good compatibility (>98% agreement) for determining the number of prey deliveries, prey species delivered, and chick and adult behavior. We consequently pooled both data sets. We recorded adult nest attendance, number and type (class and species when possible) of prey delivered, and eaglet behavior (standing, feeding, preening, fighting with siblings, exercising wings, playing with nest material, and walking around the nest; Warnke et al. 2002). All behaviors except “standing” were considered “active.” We classified prey items into four length categories (7- 15 cm, 15-23 cm, 23-30 cm, 30-40 cm) using the prey item’s size relative to adult bill or toe-pad length. Prey length and species was then used to estimate biomass using equations and experimental values from the liter- ature as described by Dykstra et al. (1998) and Gill and Elliott (2003). Our analyses focused on the relationships between variables and prey deliveries (rather than energy delivered) as prey-delivery rates were estimated with greater certainty. Environment Canada weather stations at Ucluelet (west coast) and Crofton (east coast) provid- ed weather data. Statistical Analyses. Statistical analyses were performed using STATISTICA. Data for individual nests were pooled on each coast if an analysis of covariance (ANCOVA) gave no significant difference among nests. We pooled the data for both coasts if the interaction term (coast X variable) was not significant. We used a multiple linear regression to examine the effects of adult nest atten- dance (percent of each day when at least one adult was present, averaged over each week) , mean daily tempera- ture, and chick age (independent variables) on mean daily prey and energy deliveries, averaged over each week (dependent variables). Within this multiple linear re- gression, we used ANCOVAs to compare prey deliveries on days with and without rain on each coast and to com- pare prey deliveries relative to temperature on each coast. In addition, we employed multiple linear regres- sion, using a quadratic model, to examine the effect of tide height, time of day, and prey deliveries (hourly mean) between coasts. Prior to using parametric statis- tics, we tested for homogeneity of variance (Levene’s test) and normality (Kolmogorov-Smirnov) . Bonferroni adjustments were completed on multiple comparisons We considered results to be significant if P < 0.05. The values reported are means ± SD. Results All nestlings present at the beginning of the study period survived to the end of the study pe- riod, with more young produced at the sampled nests on the east coast (2 young per occupied nest) than on the west coast {x — 1.2) of Vancouver Is- land (Table 1). Factors Influencing Provisioning Rates. Prey-de- livery rates varied significantly between coasts. The west coast had fewer prey deliveries (? = 2.3, df = S, P= 0.008) per day and lower mean prey biomass (^ — 1.9, df = 8, P = 0.04) than the east coast (Table 1). However, there was no difference (t — 2.2, df = 10, P = 0.43) in the mean daily energy delivered (Table 1). There was also no difference in the prey-size distributions {t = 0.73, df = 3, P = 0.25) for Pacific herring (Clupea harengus), the only species for which there was significant overlap between the two coasts (Table 2). A multiple linear regression (P^ ^ fl.22, P = 2.61, df - 2103, P = 0.07) indicated no correlation between nestling age and the number of prey deliveries {t = 1.34, df = 202, P = 0.66). However, there was a peak in prey deliveries at about 4 wk, corresponding to the period of maximum growth (Warnke et al. 2002). Using this regression we found a negative relation- ship between mean daily temperature and number of prey deliveries (t = —2.35, df = 202, P = 0.02), and the mean number of prey deliveries and the presence of rain on the west coast {t — —3.6, df = 103, P < 0.001), but not on the east coast {t — 0.65, df = 98, P = 0.54). In addition, prey-delivery rates at both coasts were strongly influenced by the time of day (Fig. 1). On both coasts, there was a significant quadratic relationship between tide 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. Nest ID No. Nestlings Observations Prey-Delivery Rate Energy Delivered 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 heights. Therefore, we reject the hypothesis that provisioning rates were negatively related to tide height, at either coasts, and accept the hypothesis that provisioning rates were negatively correlated with rain only on the west coast. Adult and Nestling Behavior. On both coasts, adult nest attendance was positively correlated with brood size (r = 0.33, P < 0.01) and mean number of prey deliveries per hour per eaglet (r = 0.34, P < 0.002; Fig. 3) , and negatively correlated with ea- glet age (r = 0.27, P < 0.01). Mean daily eaglet activity levels were higher on the west coast (42 ± 5% of the day) than east coast (27 ± 3%) of Van- couver Island. Eaglets on the west coast spent more time standing, feeding, preening, fighting with sib- lings, exercising wings, playing with nest material, and walking around the nest than their counter- parts on the east coast. On both coasts, eaglet mean daily activity was independent of hatching order (P > 0.6), negatively correlated with adult nest attendance (r — 0.46, P < 0.001) and positive- ly correlated with eaglet age (r = 0.34, P < 0.005; Fig. 4). Prey Type. There was considerable variation in prey type between the east and west coasts. Fish made up the majority of the diet at both locations (Table 2). However, on the east coast the most common prey item was plainfin midshipman (Po- rychthys notatus) while on the west coast it was Pa- cific mackerel {Scomber japonicus). At both loca- tions, Pacific herring {Clupea harengus) was the second most common prey item. Direct observa- tions tend to overrepresent easily identified, com- mon species so that actual percentages for major prey items may be exaggerated (Mersmann et al. 1992, Dykstra et al. 1998). Discussion Bald Eagle provisioning rates were clearly influ- enced by time of day, tide, and weather. High pro- visioning rates tended to be at intermediate tide heights, at low temperatures, during rainless peri- ods, and early during the day. The decline in pro- visioning rate with time of day likely reflects both nestling satiation and declining prey activity, as Watson et al. (1991) reported in the Columbia Riv- er estuary. The mean prey-delivery rate for Vancouver Is- land eagles (5.4 prey/d) was remarkably similar to the benchmark of 5.2 prey/d reported by Warnke et al. (2002), which they considered to indicate ad- equate prey availability to support high Bald Eagle reproductive success. Our data support this bench- mark, as territories on the east coast had consis- 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) Flounder (Bothidae/Pleuronectidae 5.0 1 3075 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) Flounder (Bothidae/Pleuronectidae 1.9 1 1343 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 1. Linear regression of mean number of prey deliveries per hour relative to time of day at Vancouver Island Bald Eagle nests in 1996 (prey deliveries = —0.033 [time of day] + 0.0458; -fi = 0.50). Data were pooled for east and west coasts. Figure 2. Quadratic regression of provisioning rates for Bald Eagles on the east ( ♦) and west (■) coasts of Van- couver Island during 1996 relative to tide height (east: prey deliveries = —0.75 X [tide height]^ + 0.25 X [tide height] — 0.016, = 0.69; west: prey deliveries = —0.052 X [tide height]^ + 0.16 X [tide height] + 0.02V; = 0 . 68 ). 6 Elliott et al. VoL. 39, No. 1 Figure 3. Vancouver Island Bald Eagle adult nest atten- dance (percent of total observation time when adult was at nest) relative to prey-delivery rate (prey deliveries per chick per hr). Each data point represents one nest, av- eraged over the 1996 season (prey deliveries = 0.0016 [adult nest attendance] + 0.22; = 0.12). coast, a region with consistently low productivity, were below this benchmark. Despite the difference in number of prey items and biomass delivered, the total energy delivered per chick was higher on the west coast than the east coast, although the mean total energy delivered to the nest was similar, as east coast nests averaged more chicks. Nestlings on the west coast met the field energetic require- ments of 2427 ±100 kj/d for nestlings in northern Wisconsin (Dykstra et al. 2001a), while those on the east coast did not. Nestlings may have experi- enced higher energetic demands on the west coast due to substantially cooler conditions more similar to Wisconsin. Eagles on the west coast foraged pri- marily on Pacific mackerel, a high-energy species (1713 kj; Ann 1973) that was unusually abundant due to surface water warming in the late 1990s (Gill and Elliott 2003). Thus, eagles on the west coast seem to make up for the low quantity of prey delivered by increasing prey quality (Wright et al. 1998, Hilton et al. 1998), as has been known to occur in other raptors (Barton and Houston 1993) . Many studies have shown a strong relationship between food abundance and reproductive success m raptors. For example, reproductive success in many temperate and arctic raptors closely follows changes in small mammal populations (e.g., Mc- Invaille and Keith 1974, Smith et al. 1981, Korpi- maki 1992, Wiehn and Korpimaki 1997), while fish abundance influences productivity in piscivores such as Ospreys (van Daele and van Daele 1982), White-tailed Sea Eagles (Helander 1985), African Fish-Eagles (Harper et al. 2002), and Bald Eagles (Hansen 1987, Dzus and Gerrard 1993). Our re- sults demonstrate one mechanism by which prey Figure 4. Mean Bald Eagle nestling activity (A — percent of total observation time when nestling was active) and adult attendance (I — percent of total observation time when adult was present) relative to nestling age (nestling activity = 6.1 X age — 3.5; = 0.92; adult attendance = — 11.3 X age + 97; = 0.87). Nests {N = 13) were stud- ied on Vancouver Island in 1996. availability can affect spatial variation in productiv- ity. The east-coast population, which consistently produced more young than needed to replace in- dividuals lost to mortality (Elliott et al. 1998), had higher prey-delivery rates than the west-coast pop- ulation, which did not produce enough young to compensate for mortality (Elliott et al. 1998) . The relationship between tide height and pro- visioning rates highlights the importance of tidal flats for nesting eagles. The influence of tide on Bald Eagle foraging habits has been documented in Alaska (Ofelt 1975, Wilson and Armstrong 1998), British Columbia (Hancock 1964, Elliott et al. 2003), and Washington (Watson et al. 1991, Garrett et al. 1993), and appears to be character- istic of coastal populations in the Pacific North- west. The peak in prey deliveries at intermediate tide heights is likely because the plainfin-midship- man-breeding zone is exposed at this tide level (El- liott et al. 2003); in the Columbia River estuary, where eagles forage primarily on fish that are most easily captured in shallow water, foraging success peaks at low tide (Watson et al. 1991). Weather also influenced provisioning rates. The decline in provisioning rates with temperature likely reflects lower chick-energy demands during warm weather, while the lower provisioning rates on rainy days may reflect reduced adult foraging efficiency due to altered visibility (Grubb 1977) or prey behavior (Newton 1978). Furthermore, rain increases eagle energetic requirements by up to 21% (Stalmaster and Gessaman 1984), and adults may need to eat more during rainy days, leaving 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- delivery rates supports the conjecture that low pro- ductivity on the outer coast is partially attributable to harsh and unpredictable weather (Gende et al. 1997, Elliott et al. 1998). Storms impact the repro- ductive success of other raptors. For example, win- ter severity delays reproduction and reduces pro- ductivity in Bald Eagles from northern Saskatchewan (Gerrard et al. 1992), as well as Golden Eagles (Tjernberg 1983, Steenhof et al. 1997) and Gyrfalcons (Poole and Bromley 1988), while hail storms caused >30% of the reproductive failure in Swainson’s Hawks in North Dakota (Gil- more and Stewart 1984). Food availability may also impact nestling surviv- al indirectly. Adults with high prey-delivery rates have higher nest attendance, because eagles that are more successful hunting can spend less time foraging (Watson et al. 1991), reducing eaglet mortality through predation or exposure. This is particularly critical during the first 4 wk when in- creased nest attendance aids in nestling thermo- regulation (Warnke et al. 2002). Brown (1993), Knight and Knight (1983), Han- sen (1986), Knight and Skagen (1988), Watson et al. (1991), and Bennetts and McLelland (1997) showed that the ability of eagles to obtain food in- creases with age. As with many other bird species, reproductive success in raptors usually increases with age (Newton 1998); fecundity peaks at age 5 yr among Eurasian Sparrowhawks (Accipiter nisus; Newton and Rothery 2002) and at age 7 yr among Northern Goshawks {Accipiter gentilis] Nielsen and Drachmann 2003), declining thereafter in both species. In addition adult-adult Spanish Imperial Eagle {Aquila adalberti) pairs monopolize high quality territories, hence have higher average fe- cundity than Juvenile-juvenile pairs (Ferrer and Bisson 2003). Therefore, older individuals presum- ably provision at higher rates than younger ones. We did not know the age of adults in our study, and this factor may explain some of the variability between individual nests. Examination of prey remains at nests from both study areas suggested that birds were the primary food source, as have most prey remains studies in the Pacific Northwest (e.g., Norman et al. 1989, Vermeer et al. 1989, Vermeer and Morgan 1989, Knight et al. 1990, Watson 2002). However, birds made up less than 7% of prey at either location during our study, as revealed by direct observation. The major prey source at both locations in our study was fish (Table 2), outlining the importance of using direct observations, as analysis of prey re- mains at nests often leads to the underestimation of fish prey (Todd et al. 1982, Mersmann et al. 1992). For comparison, the proportion of fish in diets of eagles nesting in coastal regions varied from 42% in Louisiana (Dugoni et al. 1986) to 71% in the Columbia estuary (Watson et al. 1991), and 76-85% in southeastern Alaska (Ofelt 1975). While Watson et al. (1991) noted that several eagle pairs in the Columbia River estuary were “special- ists,” preferentially taking certain food species, such as waterfowl, relative to other eagle pairs, we found no such specialization. Any variation in diet breadth could be traced to differences in local food availability, such as the presence of large tidal flats near nests that consumed large numbers of plainfin midshipman. We conclude that time of day, temperature, rain- fall, and tide height all impact eagle provisioning rates, and therefore, adult nest attendance and chick activity. Our results support the hypotheses advanced by Elliott et al. (1998) and Gill and Elli- ott (2003) that nesting success is greater on the east coast because there are more tidal flats and fewer storms. Steenhof et al. (1997) documented similar results for Golden Eagles in Idaho, in which reproductive success was determined by prey (black-tailed jackrabbit [Lepus californicus] ) abun- dance and weather (frequency of hot days) . Acknowledgments C. Hurd, C. Coker, S. Lee, and R. Gill aided during observations. D. Haycock climbed all nest trees with grace and style. D. and C. Braggins, the Mounts, R. Hop- ping, A. and J. Caldwell, and S. Napier graciously allowed access to their property. D. Henry and G. Biscall provided valuable information on Bald Eagle use of their fish by- catch. The Canadian Wildlife Service, a Simon Fraser University Graduate Research Fellowship, and the Bald Eagle Rescue and Research Foundation provided fund- ing. We are especially grateful to J. Bednarz, C. Dykstra, M. Hipfner, B. Steidl, K. Warnke, and J. Watson. Their comments greatly improved this manuscript. A. Fabro lo- cated some obscure literature. Literature Cited Ann, H.B. 1973. Studies on the age and growth of the jack mackerel {Trachurus japonicus). Bull. Fish. Res Agency 10:73—82. Anthony, R.G. 2001. Low productivity of Bald Eagles on Prince of Wales Island, southeast Alaska. J. Raptor Res 35:1-8. , 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 Bald Eagle population. Wildl. Soc. Bull. 22:576-582. , M.J. Garrett, and C.A. Schuler. 1993. Environ- mental contaminants in Bald Eagles in the Columbia River estuary./. Wildl. Manag. 57:10-19. , A.K. Miles, J.A. Estes, and F.B. Isaacs. 1999. 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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 indivi- duos 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 pro- medio 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- gles {Haliaeetus leucocephalus) from northern Ca- nadian natal areas to southern wintering grounds has long been known (Gerrard et al. 1978). Band- ing and radiotagging eagles have produced limited ^ Email address: dlang@bsc-eoc.org results (Gerrard et al. 1992). With the advance- ment of satellite-telemetry technology, information on the ecology and life history of raptors has been greatly expanded beyond what could possibly be gathered during decades of conventional telemetry and banding (Meyburg et al. 1995, Ueta et al. 2000, 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 behavior, movements, and survival of juvenile Bald Eagles have been documented from Florida (Wood et al. 1998), Saskatchewan (Gerrard et al. 1978, Harmata et al. 1985), Wyoming, California (Hunt et al. 1992), Texas (Mabie et al. 1994), and Colo- rado (Harmata 2002) . Little is known about eagle activities beyond their first winter, limiting our knowledge pertaining to juvenile stopover habitats, migratory flyways (McClelland et al. 1994, 1996), and sources of possible mortality (Buehler et al. 1991). Furthermore, little information is available regarding distribution, nesting chronology, and mi- gration timing and routes on the eastern Canadian population of Bald Eagles in Labrador. Wetmore and Gillespie (1976) conducted initial investigations of Bald Eagles in Labrador, and since 1991, the Canadian Department of National De- fence (DND) has been monitoring nest sites and productivity through annual surveys (DND 1995). To date, there are some 30-40 known Bald Eagle nest sites in Labrador (T. Chubbs unpubl. data). As part of a larger study investigating the move- ments of raptors within and out of Labrador (Laing et al. 2002), we implemented a satellite-te- lemetry program to track five hatch-year Bald Ea- gles from August 2002-August 2003. Study Area and Methods Our study took place within the Low Level Training Area (LLTA) for fighter aircraft, covering an area of ca. 130 000 km^ spanning the Labrador-Quebec northeast- ern border. We searched for occupied raptor nests in the vicinity of the Smallwood Reservoir, ca. 6700 km^ of cen- tral Labrador. This area consists of water bodies, promi- nent rocky islands, isolated erratics, and rock outcrops. Surrounding the reservoir are shorelines under 1 m of water and that are littered with driftwood, while beyond the waterline are stands of black spruce {Picea mariana) . Wetlands in this low subarctic ecoclimate are subject to permafrost. This region has a mean annual tempera- ture of — 3°C, a mean summer temperature of — 9°C, and a mean winter temperature of — 16°C (Meades 1990). De- pending on latitude, the mean annual precipitation ranges from 700-1000 mm (McManus and Wood 1991). Bald Eagles typically nest along rivers and large reservoirs in dominant white birch {Betula papyrifera), balsam fir {Abies balsamea), larch (Larix laricina), poplar {Populus hal- samifera), and black spruce at a height of 15-30 m (Bider and Bird 1983). We have observed eagle nests in all of these tree species in Labrador. Rock pinnacles and trees are used by nesting Bald Ea- gles in Labrador. However, due to the inaccessibility and remoteness of tree nests, hatch-year eagles (8-10 wk) were captured from rock nests situated in lakes and res- ervoirs. Nests were accessed using a ladder or by moun- taineering techniques, and birds were removed by hand from the nest to an adjacent area, where birds were pro- cessed and banded. Once captured, eagles were fitted with 95-g, battery-powered PTT-100 transmitters (Micro- wave Telemetry Inc., Columbia, MD U.S.A.) affixed in a backpack harness fashion using Teflon ribbon (Bally Rib- bon Mills, Bally, PA U.S.A.). Each transmitter was set with a preset duty cycle to transmit to satellite more frequently (8 hr on, 48 hr off) during possible periods of migration, most frequently during October and March and less fre- quently during summer and winter months. All eagles were banded with a U.S. Geological Survey aluminium- rivet band on one tarsus and a colored-metal-alphanu- meric-rivet band (Acraft Sign and Nameplate Co. Ltd., Edmonton, Alberta, Canada) on the other. We monitored eagle movements using the Argos Data Collection services (ARGOS 2000) . We determined nest- ing sites, stopover details, wintering areas, and migration routes using the location data received via satellite. Prior to processing, we put location data into a database using a Geographic Information System (GIS), and movement was then analyzed using ESRI® ArcView 3.2 (ESRI, Red- lands, CA U.S.A.) in combination with the Animal Move- ment Extensions program (Hooge and Eichenlaub 1997). The Argos System divides data into different classes based on validation and number of messages re- ceived. Location classes (LC) are ranked by accuracy (3>2>1>0>A>B>Z; accurate to least accurate) by Ar- gos; however, we found that several locations per trans- mission period were sufficient to document raptor move- ments if reviewed individually. Location validity and accuracy were further determined by comparing consec- utive locations to previous locations resulting in a move- ment estimate. Using this screening method we were able to include more than one transmission per reporting pe- riod, independent of location class and quality index Therefore, based on existing literature demonstrating mean juvenile eagle rates of movement (Buehler 2000), we accepted a location if the movement estimate report- ed for a bird was 0 km/d, but rejected it if the movement estimate was greater than 500 km/d. We then compiled a database comparing the number of locations used for analysis and divided this number by location estimates received to determine a percentage of viable-satellite transmissions (LC Z-transmissions were removed and not used in estimates). As the transmitters were programmed following a pre- determined duty cycle (i.e., September-October 8 hr on and 48 hr off, and November-December alternated be- tween 8 hr on and 72 hr off and 8 hr on and 168 hr off) , exact dates of departure from nesting sites and arrivals at wintering grounds are unknown. To estimate dates of arrival we considered that a raptor migrating to an area had arrived by the first date a location was obtained from that area. On departure its location was considered to be the location estimate received from within the area. An area was considered to be a stopover site if we received location estimates from an area for at least 24 hr (I^ellen et al. 2001) and the bird demonstrated concentrated lo- calized movement. Distances travelled between summer and winter grounds were calculated by adding the linear distances from the departure point to the arrival location, includ- 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- nel home-range estimator, with the Animal Movement Extensions program (Hooge and Eichenlaub 1997), which determined an estimate of the area used by the eagle. Results During the 2002 summer field season (15-30 Au- gust) five juvenile eagles were captured and fitted with PTTs. We recorded 6472 locations between 15 August 2002-30 August 2003. Of these, 75% were used in analysis. A mean of 966 locations per eagle was collected with only the most-likely locations plotted using CIS (0% Z, 20% B, 19% A, 32% 0, 22% 1, 5% 2, and 2% 3). Of those captured, eagles 37414 and 37413 and eagles 37412 and 37415 were siblings, respectively, and 37411 was captured alone. Movements before Fall Migration. Eagles re- mained within their natal area for a mean of 74 d following transmitter attachment, with departures as early as 7 October 2002 and as late as 12 Novem- ber 2002, and a median departure date of 26 Oc- tober 2002. Each bird exhibited exploratory flight patterns, and used a mean range of 165 km^ (97- 252 km^) around original capture sites. Fall Migration. During autumn migration, the eagles averaged five stopovers prior to reaching their wintering destinations, with stays ranging be- tween 24 hr and 25 d. The eagles took between 5- 95 d to reach their wintering areas, with straight- line distances between natal areas and wintering areas ranging from 510-930 km (Fig. 2). Eagle 37414 (Fig. 1) travelled the shortest linear route south, probably departing its nest site on 13 November 2002. Generally, the relatively infre- quent location estimates from Argos were insuffi- cient for tracking the birds’ routes, and therefore, there were likely deviations from a straight line. However, during fall (and spring) migrations we received location estimates as often as once every 2 d, suggesting that our estimates represented fair delineations of movement. The next transmission date for eagle 37414, 18 November 2002, was lo- cated along the northern coast of the Gulf of St. Lawrence, 472 km from its natal area. This bird wintered, and remained, in the gulf area through the spring migration period. The remaining four eagles stopped along the north shore in Quebec, continued southwest, and avoided crossing the Gulf of St. Lawrence. Eagles 37412 and 37415 (Fig. 1) took similar routes southwest, stopped at Lake Ontario, and wintered in Virginia and West Virginia, respective- ly. Eagle 37412 had four stopovers before reaching its wintering grounds of Albany, NY, on 1 Decem- ber 2002, travelling more than 2444 km after leav- ing its natal area. Eagle 37415 had six stopovers prior to reaching its wintering grounds of Orange County, VA, on 5 February 2003, ca. 1370 km from its natal area. Eagles 37411 and 37413 (Fig. 1) left the Gulf of St. Lawrence and moved toward the U.S.A. east coast, stopping along the borders of VT and NH. Eagle 37411 made 11 stopovers and travelled ca. 1420 km before reaching its wintering grounds along the Hudson River between Ulster and Dutch- ess counties, NY. Eagle 37413 travelled ca. 1640 km before settling in Hartford County, CT, with half the number of stopovers. Movements before Spring Migration. The mean overwintering period was 76 d, (44—124 d), except for 37414 which remained on wintering grounds. Spring Migration. We defined spring migration as the period of time in which the birds departed from wintering grounds and arrived at summering grounds. Once on the summering grounds, the ea- gles did exhibit exploratory and nomadic flight be- haviour. Eagle 37414 did not migrate in the spring; however, it moved within the same 252 km^ area for the whole summer and did not venture away from the Gulf of St. Lawrence. Departure dates for the four remaining eagles were between 11-27 March 2003. The birds had two to six stopovers prior to reaching the Gulf of St, Lawrence. Three of the four eagles (Fig. 2) used similar routes as taken during fall migration to travel north, with the exception of 37415 which travelled more easterly. Eagle 37415 did not stop at Lake Ontario when travelling north in the spring and meandered west of its original autumn route (Fig. 2). All of the eagles were tracked to the Gulf of St. Lawrence; two eagles continued further north to the Quebec and Labrador border for the summer. All four birds arrived at the north shore of Gaspe, Quebec, between 11-30 April 2003, av- eraging 32 d on migration. Eagle 37413 left its wintering ground first on 10 March 2003, travelling northeasterly for 1100 km with three stopovers and arriving at the Gulf of St. Lawrence on 21 April 2003. Comparatively, eagles 37412 and 37415 left their wintering grounds at similar times and travelled 1955 km and 1600 km to arrive at the Gulf of St. Lawrence on 21 and 26 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- elled 790 km to its summering grounds with three stopovers to arrive at the Gulf of St. Lawrence on 9 April 2003. Eagle 37413 divided its summer activities be- tween the Gulf of St. Lawrence and New York State. Eagle 37415 was located on the Quebec and New Brunswick borders on 1 May 2003 (Eig. 2) and moved south again to New York on 15 May 2003. It then returned to the Gulf of St. Lawrence on 8 June 2003. On 12 August 2003, this bird began moving south to New York. Eagles 37411 and 37412 left the Gulf of St. Law- rence between 3-6 May 2003 (Eig. 2). Eagle 37411 flew 400 km to the Caniapiscau Reservoir (Que- bec) and later spent time at the Ossokmanuan Res- ervoir (Labrador). Eagle 37412 travelled 617 km north and spent its summer at the Smallwood Res- ervoir. All eagles moved sporadically during the sum- mer period, with most location estimates indicating activities on the north shore of the Gulf of St. Lawr- ence. Discussion The departure of juvenile Bald Eagles from their natal nest sites in Labrador has become more pre- dictable with the application of satellite technolo- gy. Juvenile Bald Eagles from Labrador migrated south or southwest, consistent with previous juve- nile Bald Eagle migration reports (Gerrard et al. 1978, 1992, Hunt et al. 1992, McClelland et al. 1994, 1996, Harmata et al. 1999, Harmata 2002). Autumn movement was south toward the Gulf of St. Lawrence prior to dispersing en route to win- tering areas. We know from previous studies that juvenile mi- gration may be initiated by changes in foraging op- portunities (Hodges et al. 1987, Hunt et al. 1992, McClelland et al. 1994, Restani et al. 2000, Hoff- man and Smith 2003) , with birds departing an area if prey is not readily available. Hunt et al. (1992) suggested that eaglets first leave on exploratory or foraging flights and return to nest sites throughout the day for possible food provisioning by adults. What specific cue triggers migration in Labrador eagles is not known. In the weeks following fledg- ing, all five juvenile eagles remained in natal areas and exhibited exploratory flights within a 40-km radius of original nest areas, occasionally returning to the nest. Autumn departure may have been partially linked to weather or foraging opportunities. Be- cause all five eaglets were captured at the same lat- itude and longitude, they were exposed to many of the same weather conditions. Therefore, weather characteristics such as the first snow fall or frost event could have contributed by triggering the ini- tiation of migration of individuals. Conversely, Har- mata et al. (1999) stated that juveniles may exhibit movement that is individually characteristic of the juvenile and exclusive of foraging opportunities. Montana juvenile eagles (McClelland et al. 1996) departed their natal territories between 22 August— 5 October (median = 9 September, N ~ 5) , Saskatchewan juveniles left at the beginning of October (Gerrard et al. 1978), and a population in southern California departed between 19 July- 22 August (Hunt et al. 1992). More northern stud- ies have documented movement from northern Saskatchewan as late as 3 November (Harmata et al. 1999). Generally, Labrador eagles migrated south late in the season (median = 26 October). While the four eaglets travelled independently of one another, some went in a similar direction (i.e., southwest of natal areas), moving between lakes and rivers and exploiting aquatic environ- ments. They made several stopovers along the way, most near larger water-bodies such as the Gulf of St. Lawrence, Lake Ontario, and Lake Champlain. Gerrard et al. (1978) believed that juveniles fol- lowed rivers and were found near lakes as these areas represented favourable habitat. Montana ea- gles also made stops, sometimes for weeks at a time, enroute to wintering areas (McClelland et al. 1994, 1996). These stops provided an opportunity for eaglets to replenish nutrients lost during mi- gration. Restani et al. (2000) elaborated on the functional response on stopovers made by migrant Bald Eagles through Montana. They found that the eagles stopped while passing through a corridor, 80-130 km wide, around the Hauser Reservoir, Glacier National Park. The eagles detected conspe- cifics foraging from 40-65 km away and then trav- elled into the area to feed. The birds used this res- ervoir as a stopover during both northward and southward migrations. We documented the use of the St. Lawrence River and the Gulf of St. Law- rence as both spring and autumn migration stop- overs for Labrador juvenile eagles. The mean trav- elling distance from wintering to summering grounds was 350 km less than the distances trav- elled from natal areas to winter grounds. We sus- pect that Labrador eagles gained experience dur- March 2005 Eagle Migration from Labrador 17 ing their autumn migration, and that their flight routes and strategies were more defined and less nomadic in the spring. Eagles may improve their sense of direction on northern flights through vi- sual cues, mentally catalogued stopovers (Hake et al. 2001), and increased flight experience. Spring departure of juveniles occurred between 11-27 March 2003, and the four migrating eagles used the Gulf of St. Lawrence fall stopover (me- dian = 21 April 2003) prior to arriving at sum- mering grounds (between 3-6 May 2003). Non- breeding birds are more apt to spend time away from optimal nesting areas and focus on favour- able foraging sites rather than establishing a breed- ing territory (Jenkins et al. 1999). Based on the survival of our five PTT-tagged birds, the Gulf of St. Lawrence was a suitable stopover site, and pro- vided adequate foraging habitat for travelling Bald Eagles. Acknowledgments This project would not have been possible without the funding support of the Goose Bay Office, Department of National Defence, Canada. We also acknowledge the sup- port of McGill University, Gary Humphries, and the De- partment of Tourism, Culture and Recreation (Endan- gered Species and Biodiversity Section). We thank M. Solensky for demonstrating proper transmitter attach- ment techniques and for assisting in the field. We thank L. Elson, G. Goodyear, and P. Trimper for their help in the field. We are grateful to Capt. (N) K.D. Laing for his editorial assistance. We also thank M. Fuller, M. Restani, and M. Goldstein for comments that greatly improved the manuscript. Literature Cited Argos. 2000. User’s manual. Service Argos, Inc., Largo, MD U.S.A. Bider, J.R. AND D.M. Bird. 1983. Distribution and densi- ties of Osprey populations in the Great Whale Region of Quebec. Pages 223-230 in D.M. Bird, N.R. Sey- mour, andJ.M. Gerrard [Eds.], Biology and manage- ment of Bald Eagles and Ospreys. Harpell Press, Ste. Anne de Bellevue, Quebec, Canada. Buehler, D.A. 2000. Bald Eagle {Haliaeetus leucocephalus) . In A. Poole and F. Gill [Eds.], The birds of North America, No. 506. American Ornithologists’ Union, Washington, DC U.S.A. , J.D. Fraser, J.K.D. Seegar, and G.D. Therres. 1991. Survival rates and population dynamics of Bald Eagles on Chesapeake Bay. J. Wildl. Manag. 55:608- 613. Department of National Defence. 1995. An environ- mental impact statement on military flying activities in Labrador and Quebec. Goose Bay National De- fence Headquarters Project Office, Ottawa, Ontario, Canada. Gerrard, J.M., D.W.A. Whitfield, P. Gerrard, P.N. Ger- rard, AND W.J. Maher. 1978. Migratory movements and plumage of subadult Saskatchewan Bald Eagles CMn. Field-Nat. 92:375-382. , P.N. Gerrard, G.R. Bortolotti, and E.Z. Dzus. 1992. A 24-year study of Bald Eagles on Besnard Lake, Saskatchewan./. Raptor Res. 26:159—166. Hake, M., N. I^ellen, and T. Alerstam. 2001. Satellite tracking of Swedish Ospreys Pandion haliaetus: autumn migration routes and orientation./. Avian Biol. 32:47- 56. Harmata, A.R. 2002. Vernal migration of Bald Eagles from a southern Colorado wintering area. /. Raptor Res. 36: 256-264. , J.E. Toepfer, and J.M. GERRard. 1985. Fall mi- gration of Bald Eagles produced in northern Sas- katchewan. Blue Jay 43:232-237. , F. Montopoli, B. Oakleaf, P. Harmata, and M. Restani. 1999. Movements and survival of Bald Eagles banded in the greater Yellowstone ecosystem. /. Wildl Manag. 63:781-793. Hodges, J.L, E.L. Boeker, and A.J. Hansen. 1987. Move- ments of radiotagged Bald Eagles, Haliaeetus leucoce- phalus, in and from southeastern Alaska. Can. Field- Nat. 101:136-140. Hoffman, S.W. and J.P. Smith. 2003. Population trends of migratory raptors in western North America, 1977- 2001. Con^/or 105:397-419. Hooge, P.N. AND B. Eichenlaub. 1997. Animal move- ment extension to ArcView, Ver. 1.1. Alaska Biological Science Center, U.S. Geological Survey, Anchorage, AK U.S.A. Hunt, W.G., R.E. Jackman, J.M. Jenkins, C.G. Thelan- der, and R.N. Lehman. 1992. Northward post-fledging migration of California Bald Eagles. /. Raptor Res. 26. 19-23. Jenkins, J., R. Jackman, and W. Hunt. 1999. Survival and movements of Bald Eagles fledged in northern Cali- fornia. /. Raptor Res. 33:81-86. I^ellen, N., M. Hake, and I. Alerstam. 2001. Timing and speed of migration in male, female, and juvenile Os- preys Pandion haliaetus between Sweden and Africa as revealed by field observations, radar and satellite tracking./. Avian Biol. 32:57-67. Laing, D.K., D. Bird, T. Chubbs, and G. Humphries 2002. Migration routes, timing, and nest site fidelity of Osprey {Pandion haliaetus) and Bald Eagles {Hal- iaeetus leucocephalus) as they relate to military aircraft activity in Labrador. Pages 82-92 in B. MacKiinnon and K. Russell [Eds.], BirdStrike 2002 conference proceedings, August 19-21 2002. Transport Canada, Toronto, Ontario, Canada. Mabie, D.W., M.T. Merending, and D.H. Reid. 1994. Dis- persal of Bald Eagles fledged in Texas. /. Raptor Res 28:213-219. 18 Laing et al. VoL. 39, No. 1 McClelland, B.R., L.S. Young, P.T. McClelland, J.G. Crenshaw, H.L. Allen, and D.S. Shea. 1994. Migra- tion ecology of Bald Eagles from autumn concentra- tion in Glacier National Park, Montana. Wildl. Monogr. 125:1-61. — , P.T. McClelland, R.E. Yates, E.L. Caton, and M.E. McFadzen. 1996. Fledging and migration of ju- venile Bald Eagles from Glacier National Park, Mon- tana. J. Raptor Res. 30:70-89. McManus, G.E. and C.H. Wood. 1991. Adas of New- foundland and Labrador. Breakwater, St.John’s, New- foundland, Canada. Meades, S.J. 1990. Natural regions of Newfoundland and Labrador. Protected Areas Association, St. John’s, Newfoundland, Canada. 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- lite. Ostrich 66:135-140. Restani, M., a. Harmata, and E. Madden. 2000. Numer- ical and functional responses of migrant Bald Eagles exploiting a seasonally concentrated food source. Con- dor 102:561-568. Ueta, M., F. Sato, H. Nakagawa, and N. Mita. 2000 Migration routes and difference of migration sched- ule between adult and young Steller’s Sea Eagles Hal- iaeetus pelagicus. Ibis 142:35-39. Wetmore, S.P. and D. Gillespie. 1976. Osprey and Bald Eagle populations in Labrador and northeastern Que- bec, 1969-73. Can. Field-Nat. 90:330-337. Wood, P.B., M.W. Collopy, and C.M. Sekerak. 1998. Postfledging nest-dependence period for Bald Eagles in Florida./. Wildl. Manag. 62:333-339. Received 23 March 2004; accepted 16 November 2004 Associate Editor: Michael I. Goldstein J Raptor Res. 39(l):19-25 © 2005 The Raptor Research Foundation, Inc. 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 cate- goria (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’ jpdelong@comcast.net 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 has attracted considerable research attention for decades (Able 1999). The migration of some birds remains poorly understood, however. The Flam- mulated Owl ( Otus flammeolus) is a small, nocturnal bird whose migration patterns are among the least known in North America (McCallum 1994). The available evidence suggests that these owls are Neo- tropical migrants (McCallum 1994). This view is derived primarily from the near absence of winter records for Flammulated Owls in North America. These negative results have not been accompanied by positive data demonstrating where Flammulated Owls in North America spend the winter. We que- ried the Bird Banding Laboratory database and found that, through the year 2000, no band recov- eries were obtained that directly documented the migratory movements of Flammulated Owls. We investigated the natal origins of Flammulated Owls captured in the Manzano Mountains of cen- tral New Mexico using stable-hydrogen-isotope analyses. Briefly, the latitudinal gradient in stable- hydrogen-isotope ratios (^H/^H) associated with growing season precipitation (SD^ is reflected in animal tissues that are grown in those areas (Hob- son and Wassenaar 1997). Although some hydro- gen in tissues can exchange with atmospheric hy- drogen (Wassenaar and Hobson 2000), for tissues such as feathers and hair these ratios are more or less locked into their structure and can be mea- sured even when the animal travels great distances (Chamberlain et al. 1997). Recent studies show that the ratio of stable-hydrogen isotopes in the keratin of bird feathers (8T>y) of individuals cap- tured during migration can be compared to maps of bDp to describe the approximate latitudes where those feathers were grown (Meehan et al. 2001, Wassenaar and Hobson 2001, Kelly et al. 2002). Analyses of stable-hydrogen isotopes also have re- vealed patterns of migratory movement in Neo- tropical migratory birds (e.g., leap-frog and chain migration; Kelly et al. 2002, Smith et al. 2003). We used stable-isotope analysis of Flammulated Owl feathers to answer three specific questions. First, are the owls captured at the banding station in the Manzano Mountains of local or regional or- igin, or are they primarily migrants from far north of the local breeding area? Second, is the seasonal pattern of owl captures related to the origins of the owls? Third, are there sex differences in seasonal timing of capture or in natal origins? Methods Field Methods. The study site was located near Capilla Peak in the Manzano Mountains of central New Mexico (34°42'N, 106°24'W; Fig. 1; DeLong and Hoffman 1999). We captured owls at two netting stations spaced ca. 200 m apart on the east and west sides of the Capilla Peak Ridge. We lured owls to the stations with broadcast Flam- mulated Owl calls placed within an array of three to six mist nets (60-mm mesh). We opened mist nets 3-7 nights/wk from 19 August-20 October 2002, for a total of 51 nights of netting. We began netting ca. 0—30 min after sunset and continued until 15-30 min before sun- rise, or for shorter periods if inclement weather forced station closure. We generally opened nets only during calm or moderately-windy periods, avoiding periods of high wind (exceeding ca. 24 km/hr). We collected a contour feather from about every other owl {N = 57) for use in the isotope analysis. Because isotope ratios in adult raptor feathers may not corre- spond to local precipitation (Meehan et al. 2003), we collected feathers only from hatch-year owls. Hatch-year Flammulated Owls leave the nest in juvenal plumage and begin molting into formative plumage within about 1 wk after fledging (Reynolds and Linkhart 1987) . When they are captured at the Capilla Peak banding station, most hatch-year owls have not completed this molt (DeLong 2004). Therefore, we aged owls as hatch-years if they showed a mix of juvenile and formative feathers and col- lected only juvenile-plumage feathers for use in the sta- ble-hydrogen-isotope analysis. We took blood samples from owls for sex determina- tion. We collected blood from the brachial vein using the tip of a needle and a capillary tube and transferred the sample into a microcentrifuge tube containing ethanol. Wildlife Genetics, Inc. (Nelson, British Columbia, Cana- da) analyzed the samples and determined the sex of these owls using the CHD gene (Griffiths et al. 1998). Unless already banded, we banded all captured owls with a uniquely-numbered aluminum leg band provided by the U.S. Geological Survey. Reference Feathers. We collected reference feathers {N = 22) to calibrate the relationship between 8£y and the bDp where the feathers were grown. We obtained Flammulated Owl feathers from sites near Ogden, Utah, and Colorado Springs, Colorado, where collaborators col- lected feathers from nestlings in 2002. Additional refer- ence feathers came from collection managers at the Uni- versity of New Mexico and the University of Arizona, who provided us with feathers from study skins of hatch-year plumage Flammulated Owls taken in north-central New March 2005 Origins of Fall-captured Flammulated Owls 21 Predicted /V = 2 ( 85 to -95 o/oo) 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 Arizona. Collection dates of museum skins ranged from 1959-95. These reference feathers cover much of the Fliimmulated Owl’s range in the Rocky Mountain States. Laboratory Methods. We prepared feather samples by first cleaning them of oils with a chloroform-methanol (2:1) solution (Wassenaar and Hobson 2000) and then air drying them for 14 d to enable exchangeable hydro- gen (13-22%) to equilibrate with laboratory-ambient moisture (Chamberlain et al. 1997, Wassenaar and Hob- son 2000). We then packed feather clippings (0.18-0.20 mg) in silver capsules (3.5 X 5 mm; Costech, Valencia, CA, U.S.A.), pyrolized the samples using a Finnigjan MAT TC-EA. elemental analyzer (Thermo Electron Corpora- tion, Boston, MA U.S.A.), and analyzed sample hydrogen using a Delta*’*"® XL mass spectrometer (Thermo Elec- tron Corporation, Boston, MA U.S.A.) in continuous flow mode at the University of New Mexico Stable Isotope Laboratory. We used the following standard model to cal- culate whole-sample 8£> and report bD values in parts per thousand (%o): bD = {(hydrogen-isotope ratio of sample) (hydrogen-isotope ratio of Vienna Standard Mean Oceanic Water [VSMOW]) - 1} X 1000. The precision of our analyses was bD ± 3%o (1 SD) based on repeated measurements of internal laboratory stan- dards. We calculated the isotope ratios of non-exchangeable hydrogen in feather samples via comparative equilibra- tion using keratin standards after Wassenaar and Hobson (2003). The isotope ratios of non-exchangeable hydro- gen in keratin standards were determined using steam equilibration methods (Wassenaar and Hobson 2000). The keratin standards we used were black bear (Ursus americanus) fur samples from Louisiana (non-exchange- able hydrogen bD = — 58%o) and Alaska ( — 164%o). The comparative equilibration equation we used to convert whole-sample values to non-exchangeable values was: ®7^nor>.exchangeable (8/V^hoie^pie + 29.89)/0.65 We report both whole-sample and non-exchangeable hy- drogen-isotope ratios of reference and fall-collected feathers to facilitate comparison with other studies. Mappii^ Methods. We estimated the origins of owls captured in the Manzano Mountains by (1) calculating a regression model for the relationship between hydrogen- isotope ratios in reference feathers and estimated grow- ing season bDp for reference-feather collection sites, (2) using this regression to predict growing season bDp for each feather sampled in the Manzano Mountains, and (3) using Geographic Information System (GIS) analysis to query growing season bDp Flammulated Owl geo- graphic range, and North American biome maps to iden- tify potential origins. Estimated bDp values for the predictive regression and determination of origins were from the GIS-based model of Meehan et al. (2004; http://biology.unm.edu/wolf/ 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). Location bDf ± SD Non-Exchangeable Hydrogen Wp ± SD Whole-Sample Hydrogen N Mean Latitude Mean 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 entered this into the GIS to limit bDp map queries to geographic regions of North America where Flammulat- ed Owls breed. We used a digitized map of North Amer- ican biomes from Reichenbacher et al. (1998) to limit ^Dp map queries to dry montane conifer forests, the bi- ome selected by Flammulated Owls (McCallum 1994). Using the GIS, we selected bDp grid cells that fell within the range of predicted bDp values for birds captured at the banding station, and that occurred within both the owl’s geographic range and associated biome type (Fig. 1). We emphasize that these data should be viewed as a spatial histogram rather than precise estimators of natal origins. Results The mean values for non-exchangeable and whole-sample hydrogen from owls at the four ref- erence sites ranged over 68 %o and were progres- sively more negative with increasing latitude (Table 1). The mean 8/)^ value for captured owls in the Manzanos was between the mean values for south- ern Arizona and northern New Mexico (Table 1). The relationship between 8Z)^ and reference feather 8Tyfor non-exchangeable hydrogen — 0.47) was estimated as: 8Ty= 1.33(8Z)p + 16%o. (1) The standard errors for the non-exchangeable slope and intercept were 0.13 and 25, respectively. The relationship between 8Z)^ and bDj for whole- sample hydrogen (/? = 0.48) was estimated as; bDf= 0.87 (hDp) - 19%o. (2) The standard errors for the whole-sample slope and intercept were 0.20 and 16, respectively. We predicted a 8Z>^ value for each owl captured in the Manzano Mountains using non-exchangeable 8Ty values and reference equation (1) . There would be no difference in our results between using equa- tions (1) or (2), but we chose to proceed using equation (1). Predicted bDp values were placed into three cat- egories. Category one ranged from —30 to — 60%o {N = 45), category two ranged from —60 to — 70%o (N — 10), and category three ranged from —85 to — 95%o {N — 2). When mapped, the three categories of predicted hDp displayed potential na- tal origins of captured Flammulated Owls that ranged from the immediate local vicinity of the banding station up through the northwestern U.S.A. Owls in the first category (with the least negative bDp values) had potential origins in the isolated mountain ranges of west-central New Mex- ico and east-central Arizona (Fig. 1). Hence, most owls could have been local or from neighboring mountain ranges. Owls in the second category had potential natal origins estimated at the higher el- evations of mountain ranges near the Manzanos and in northern New Mexico and southern Colo- rado. Two owls were placed in the third category (with the most negative 8£y values) and had poten- tial origins in either the extreme high elevations of their breeding areas in northern New Mexico or in an area stretching from the Rocky Mountain front in Colorado up through northwestern states such as Oregon and Washington. We captured most owls in September, with few owls captured after the first week of October. The seasonal pattern of owl captures was not related to 8Ty values and, therefore, not likely related to the March 2005 Origins of Fall-captured Flammulated Owls 23 Figure 2. Relationship between stable-hydrogen-isotope ratios of feathers (8-Dy) and Julian capture date for hatch- year Flammulated Owls captured in the Manzano Moun- tains, New Mexico, in 2002. origins of the owls (Fig. 2). However, the two owls in the third category were captured toward the end of the banding season (mid-October; Fig. 2). It is possible that these owls were coming from further north than the other owls, suggesting these two owls were undertaking migratory movements when captured. There was no difference in values (t = 0.35, df = 31.8, P — 0.73) or Julian capture date between males and females {t = 0.61, df = 39.8, P = 0.54). Hence, there were no sex-specific differences in the predicted origins or timing of captured owls. Discussion Our results indicate that hatch-year Flammulat- ed Owls captured during fall in the Manzano Mountains represent a combination of local and regional birds, and a small number of migrants from the north (Fig. la). We divided our predicted bDp into three categories and mapped the areas where those values could be found (Fig. 1). Using this approach, we offer three general statements about the potential origins of captured owls based on the three mapped categories. In the first cate- gory, we find owls that could have originated from much of the montane areas in Arizona and New Mexico (Fig. lb). There is no evidence that young Flammulated Owls make long-distance movements to the east or west, so it is likely that the large ma- jority of captured individuals originated in central New Mexico, with many owls potentially originat- ing 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, giv- en that this area represents the largest area of po- tential origin. However, the second category in- cludes 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 from the highest elevations in New Mexico up through Washington (Fig. la). These results are one of the first pieces of evi- dence that suggest southward migratory move- ments in Flammulated Owls. At least two owls likely originated north of New Mexico, making their movement to the banding station consistent with what we would expect from migrating birds. As- suming that the direction of long-distance move- ments during the fall is to the south, then these two owls made movements of at least 200 km (and possibly much more) to arrive in the Manzanos. Although our data provide new insights into the movements of Flammulated Owls in the Manzano Mountains, our results are imprecise because of several factors that limit our ability to use hydrogen isotopes to determine the origins of particular birds. These factors are particularly difficult to overcome in the mountainous states of the south- western U.S.A. and the southern Rocky Mountains. First, the latitudinal gradient in isotope ratios al- lows only coarse predictions of potential origins (Meehan et al. 2001). Second, the latitudinal gra- dient in isotope ratios is complicated in the south- western U.S.A. due to proximity to the Pacific Ocean, the Gulf of California, and the Gulf of Mex- ico (Dansgaard 1964). Finally, the latitudinal gra- dient is complicated by a negative relationship be- tween elevation and isotope ratios (Poage and Chamberlain 2001, Bowen and Wilkenson 2002). This latter relationship makes it difficult to distin- guish potential source areas such as those at high elevations in the south from those at lower eleva- tions further north. Importantly, we used methods that accounted for the various processes determin- 24 DeLong et al. VoL. 39, No. 1 ing isotope ratios in local rainfall by mapping a relationship between 8£y values and estimated local hDp values rather than assuming a simple latitudi- nal relationship over the western United States. Despite the limitations, this stable-hydrogen-iso- tope analysis has produced a very useful picture of the natal origins of owls captured in the Manzano Mountains, a picture that would be difficult to compile using band recoveries of a small, noctur- nal bird. We also found no overall relationship between capture date and values (Fig. 2). The absence of a relationship to indicate migratory patterns such as whether northern or southern birds pass through the site first (Smith et al. 2003) may have resulted from the geographically-limited source population we sampled. There still may be inter- esting migratory patterns to detect if owls can be sampled from a larger portion of the range. The two clearly southward-moving birds were captured in mid-October, suggesting that October may be an important time for longer movements of young Flammulated Owls in New Mexico. This result is consistent with other views on the timing of Flam- mulated Owl migration (McCallum 1994). How- ever, why we captured the bulk of the owls in Sep- tember and so few owls in October, despite nets being open in late October, remains to be ex- plained. We found no gender-specific differences in cap- ture timing. We investigated this possibility because many migrating raptors show gender-specific dif- ferential migration timing (DeLong and Hoffman 1999). Such differences could mask seasonal dif- ferences in the origin of captured birds because temporal separation of owls originating in the same locations could make it difficult to accurately detect a relationship between owl origins and cap- ture date. The absence of a gender-specific timing difference reduces the possibility that we over- looked a relationship between capture date and or- igin. It is also likely that timing differences between males and females were not yet developed because these owls likely originated relatively close to the Manzanos. The breeding range of Flammulated Owls ex- tends north from the Manzano Mountains into Colorado and Wyoming and further northwest into Utah, Idaho, Montana, and Alberta, Canada (McCallum 1994). We anticipated that many cap- tured owls would have clearly come from through- out the full latitudinal extent of their range; how- ever, we identified potential natal areas for captured owls that were primarily local and region- al. Indeed, every sampled owl could have originat- ed in New Mexico (although the two potential mi- grants would be from far northern New Mexico) . We do not believe that this finding is a failure of the method. Stable-hydrogen-isotope analysis of bird feathers has been used successfully to describe source ranges for focal species at other migration monitoring stations (Wassenaar and Hobson 2001). For example, a study on Sharp-shinned Hawks {Accipiter striatus) captured during migra- tion at the Manzano Mountains study site, using procedures identical to those used in this study, confirmed that captured birds had originated across a wide latitude spanning New Mexico to Alaska (Smith et al. 2003), similar to patterns in- dicated by long-term band-recovery data (Hoffman et al. 2002). Fall movements of young Flammulated Owls in New Mexico remain somewhat of a mystery. Whether Flammulated Owls captured during fall in the Manzano Mountains are local birds or dispers- ers from other parts of New Mexico is still un- known. Finally, answering the question of what type of migratory movements Flammulated Owls undertake may require considerably more effort. Banding efforts that target potential wintering ar- eas and other likely stopover locations (in partic- ular where Flammulated Owls do not breed) may shed light on this question, especially if used in combination with further isotopic analysis or ge- netic markers that can match wintering or migrat- ing birds to potential natal areas. Acknowledgments Primary financial support was provided by the USDA Forest Service, Cibola National Forest and Region 3, and the New Mexico Game and Fish Department Share with Wildlife Program. Additional funds for the project came from Jeanie and Jodie Plumber. Beverly deGruyter at the Sandia Ranger Station, and Howard Gross and Jeff Smith at HawkWatch International were instrumental in ar- ranging funding and logistical support for this project. Wendy King and Apple Snider conducted most of the fieldwork. Bob Dickerman (University of New Mexico), Tom Huels (University of Arizona), Brian Linkhart (Col- orado College), and Diane McCabe (U.S. Forest Service, Ogden Ranger District) all provided juvenile Flammulat- ed Owl feathers from their study areas or their universi- ty’s study skin collections for use as isotope reference samples. The New Mexico Coffee Company provided Av- alon® organic, shade-grown coffee to keep field staff awake. Keith Hobson, Robert Rosenfield, Jeff Smith, and March 2005 Origins of Fall-captured Flammulated Owls 25 an anonymous reviewer provided helpful comments on this manuscript. Literature Cited Able, K.P. 1999. Gatherings of angels: migrating birds and their ecology. Comstock Books, Ithaca, NYU.S.A. Bowen, G. and B. Wilkinson. 2002. Spatial distribution of delta 0-18 in meteoric precipitation. Geology 30: 315-318. Chamberlain, C.P., J.D. Blum, R.T. Holmes, X. Feng, T.W. Sherry, and G.R. Graves. 1997. The use of iso- tope tracers for identifying populations of migratory birds. Oecologia 109:132-141. Dansgaard, W. 1964. Stable isotopes in precipitation. Tel- lus 16:436-468. DeLong, J.P. 2004. Age determination and preformative molt in hatch-year Flammulated Owls during the fall. N. Am. Bird Bander and S.W. Hoffman. 1999. Differential autumn mi- gration of Sharp-shinned and Cooper’s hawks in west- ern North America. Condor 101:674-678. Griffiths, R., M.C. Double, K. Orr, and RJ .G. Dawson. 1998. A DNA test to sex most birds. Mol. Ecol. 7:1071- 1075. Hobson, K.A. and L.I. Wassenaar. 1997. Linking breed- ing and wintering grounds of neotropical migrant songbirds using stable hydrogen isotopic analysis of feathers. Oecologia 109:142-148. Hoffman, S.W., J.P. Smith, and T.D. Meehan. 2002. Breeding grounds, winter ranges, and migratory routes of raptors in the mountain West. J. Raptor Res. 36:97-110. Kelly, J.F., V. Atudorei, Z.D. Sharp, and D.M. Finch. 2002. Insights into Wilson’s Warbler migration from analyses of hydrogen stable-isotope ratios. Oecologia 130:216-221. McGallum, D.A. 1994. Flammulated Owl (Otus flammeo- lus). In A. Poole and F. Gill [Eds.], The birds of North America, No. 93. The Birds of North America, Inc., Philadelphia, PA U.S.A. Meehan, T.D., J.T. Giermakowski, and P.M. Cryan. 2004. GIS-based model of stable hydrogen isotope ratios in North American growing-season precipitation for use in animal movement studies, hot. Environ. Health Stud 40:291-300. , C.A. Lott, Z.D. Sharp, R.B, Smith, R.N. Rosen- field, A.C. Stewart, and R.K. Murphy. 2001. Using hydrogen isotope geochemistry to estimate the natal latitudes of immature Cooper’s Hawks migrating through the Florida Keys. Condor 103:11-20. , R.N. Rosenfield, V.N. Atudorei, J. Bielefeldt, LJ. Rosenfield, A.C. Stewart, W.E. Stout, and M.A. Bozek. 2003. Variation in hydrogen stable-isotope ra- tios between adult and nestling Cooper’s Hawks. Con- dor 105:567-572. Poage, M.A. and C.P. Chamberlain. 2001. Empirical re- lationships between elevation and the stable isotope composition of precipitation and surface waters: Con- siderations for studies of paleoelevation change. Am J. Science Reichenbacher, F., S.E. Franson, and D.E. Brown. 1998 North American biotic communities map. Univ. Utah Press, Salt Lake City, UT U.S.A. Reynolds, R.T. and B.D. Linkhart. 1987. The nesting biology of Flammulated Owls in Colorado. Pages 239- 248 in R.W. Nero, R.J. Clark, R.J. Knapton, and R.H Harare [Eds.], Biology and conservation of northern forest owls. U.S.D.A. Forest Service General Technical Report RM-142, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO U.S.A. Smith, R.B., T.D. Meehan, and B.O. Wolf. 2003. Assess- ing migration patterns of Sharp-shinned Hawks Accip- iter striatus using stable-isotope and band encounter analyses. J. Avian Biol. 34:387-392. Wassenaar, L.I. and K.A. Hobson. 2000. Improved meth- od for determining the stable-hydrogen isotopic com- position (delta D) of complex organic materials of environmental interest. Environ. Sci. Tech. 34:2354— 2360. and . 2001. A stable-isotope approach to delineate geographical catchment areas of avian mi- gration monitoring stations in North America. Envi- ron. Sci. Tech. 35:1845-1850. and . 2003. Comparative equilibration and online technique for determination of non-exchange- able hydrogen of keratins for use in animal migration studies, hot. Environ. Health Stud. 39:211-217. 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; weath- er 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 diferen- cias 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: sasvari@abc.hu 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 indicate that young birds invest less in reproduc- tion than do older birds (Williams 1966, Pianka 1976), which may be due to the young birds’ poor- er condition (Coulson 1968, Pugesek and Diem 1983, Weimerskirch 1992) or their inexperience in foraging and knowledge of the habitat (Orians 1969, DeSteven 1978). Long-term studies on owls have also shown the effects of age on breeding per- formance (Recher and Recher 1969, Korpimaki 1988, Gehlbach 1989, Saurola 1989). We have shown in a previous study the effect of age com- position on breeding success of Tawny Owls {Strix aluco) and found sex-related influences on number of eggs, hatching and fledging success in first, sec- ond, and third breeding years of the pairs (Sasvari and Hegyi 2002). The aim of our recent study was to examine age-dependent reproductive perfor- mance through five consecutive breeding years of owl parents and the effect of weather both on breeding success and nest-site choice of the pairs. Southern and Lowe (1968) suggested that prey availability for Tawny Owls is determined by ground cover, and when snow prevents them prey- ing on small mammals, they switch to hunting mainly birds. Many papers have reported that throughout Europe, this species relies mostly on rodents, but will feed on birds as a secondary, al- ternative food (Southern and Lowe 1968, Gosz- ezynski 1981, Mikkola 1983, Kirk 1992,Jedrzejewski et al. 1994). We thus examined the breeding per- formance achieved by the pairs in snow years and in years when snow did not cover the ground dur- ing the incubation and early nestling periods. In addition, we recorded the distribution of nest sites at different elevations and changes in nest-site choice depending on snow condition. The Tawny Owl is a resident, strongly monoga- mous owl in central Europe that can be attracted to artificial nest boxes. We marked individual par- ents and determined the age (Petty 1992) of the pairs in the first known breeding years of the fe- males. In order to evaluate the condition of the owls, we measured the body mass of parents and both body mass and length of tarsus on nestlings before fledging. On the basis of the sexual dimorphism in Tawny Owls, we hypothesized that the lighter male off- spring, which demand less parental investment, survive better than heavier female offspring during food shortages (e.g., Olsen and Cockburn 1991, Wiebe and Bortolotti 1992, Dzus et al. 1996). If the different sex offspring require varying amounts of care, the young that demands more parental effort should be fewer in a poor-food environment re- ducing the total reproductive cost to the parents (Slagsvold 1990, Glutton-Brock 1991, Weatherhead and Teather 1991). To examine the reduction of reproductive cost by elimination of heavier off- spring, we related the body condition of nestlings before fledging to the number of breeding seasons that females were present and to the weather. Methods We placed 220 nest boxes for breeding Tawny Owls in a mixed oak-hornbeam-beech (Quercus — Carpinus — Fa- gus) forest, with 40-60-yr old trees, in the Duna-Ipoly Na- tional Park, 30 km northwest of Budapest (47°35'N; 19°02'E) during the period 1992-2004. Six to eight nest boxes were grouped together with 300-600 m between them, the groups being separated by 2-5 km. Nest boxes were checked at 4—8 d intervals beginning at the end of January. We captured 157 females and 141 males during the nestling period by placing a net over the entrance of the boxes while the birds were inside. The birds were marked with different combinations of colored rings for individ- ual identification. We identified 44 females that bred through three successive breeding seasons and 26 fe- males that bred through four seasons, and 17 females that bred through five seasons. Owls changed mates on nine occasions, but none lost their nests through preda- tion. Age of females was determined by the pattern of the primaries and secondaries (Petty 1992) in their first known breeding year and their mates were categorized as (1) of same age or younger, or (2) older. The 44 fe- males in their first known breeding year consisted of 15 1-yr old, 23 2-yr old, and six 3-yr old birds. Body mass of parents were measured when their first hatched-young were 3 d old, and fledgling masses were recorded when they were 25-28 d old. As a consequence of the 550 m altitude range of the study area (130-680 m), snow covered the ground longer 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 Years of Females Age of Males Reiated to Females Snow Cover ON THE Ground Number OF Eggs Hatching Success Fledging Success Number of 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 Second Younger or same Yes (7) 2.14 H- 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 Older Yes (8) 2.88 -h 0.89 0.91 H- 0.03 0.81 0.07 2.43 1+ 0 500 m, which included 64, 85, and 71 nest box- es for the owls, respectively. The number of nests occu- pied by the pairs in each of the three altitudinal ranges was related to the number of breeding years of the fe- males and snow condition of the given year. Statistical analyses were carried out using the SPSS sta- tistical package (Norusis 1977). Hatching success and fledging success were calculated by number of eggs hatched per number of eggs laid and number of nest- lings fledged per number of nestlings hatched, respec- tively. Percent data were arcsine transformed for para- metric analysis. Results Reproductive Performance. We found no signif- icant relationships between the breeding year of the female and male age for number of eggs and hatching success, but in all breeding years, broods with older males than the females experienced higher fledging success (Tables 1, 2). Snow con- ditions affected all categories of reproductive per- formance of females. Male age did not influence the effects of snow on clutch size and hatching suc- cess. However, broods of older males experienced higher fledging success and produced more nest- lings both in snow years and in years without snow cover. Females laid more eggs and fledged more nest- lings as they aged (combined data on age of males, ANOVA: ^4 170 = 3.77, P = 0.005; F4170 = 5.31, P < 0.001; respectively), but there were no signifi- cant differences in reproductive performances of females between their third and fifth breeding sea- sons (^2,84 = 2.97, P = 0.063; ^2,84 - 3.07, P < 0.072) . Hatching success was not influenced by the age of male related to female age (ffi J73 = 3.16, P = 0.077); however, fledging success was higher when the males were older than the females (Fj 173 = 9.17, P < 0.001; respectively). Parents achieved both higher hatching success and fledging success in years without snow cover than those with snow cover during the incubation and early nestling pe- riod (ifi 173 = 8.96, P < 0.001; fy 473 = 9.03, P < 0.001; respectively). Higher fledging success than hatching success was recorded in first and second 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 hatching success exceeded fledging success in the third, fourth, and fifth breeding years of the fe- males (ifi 42 = 11.52, P< 0.001; Ti 24 = 11.20, P< 0.001; and 15 = 8.92, P = 0.002) . Body Mass. Body mass of both females and males increased as the number of breeding years increased (female: T 4 i 7 o = 2.93, P — 0.021, male: 7^4,170 ~ 3.10, P < 0.017; Fig. 1) but there were no significant differences in body mass between the third and fifth breeding seasons (female: i^ 2 ,s 4 ~ 2.52, P = 0.087, male: = 2.69, P - 0.073). Female body mass was lower in years with snow than in years without snow cover in the first, sec- ond, and third breeding seasons, although the P values declined from the first to the third breeding years (^3 = 4.52, P < 0.001; ^43 = 3.47, P < 0.01; %3 = 2.40, P < 0.05; respectively) and there was no significant difference in fourth and fifth breeding year (% = 1.47, NS and t^Q — 1.30, P > 0.005). A similar tendency was recorded for male body mass, but the differences were lower than those of fe- males in first and second breeding years (^43 = 2.62, P < 0.02; ^43 2.28, P < 0.05; respectively) and disappeared in third, fourth, and fifth breed- ing seasons (^43 = 1.44, % = 1.16, fie = 1.30, re- spectively; P> 0.05). If the differences in mass loss between the females and males are presented as percentage mass loss in snow years in relation to mass in years without snow cover, the smaller de- crease for males than females is notable (Fig. 2). Between-year Shift in Nest Sites. Distribution of selected nest sites between the three altitude rang- es showed significant differences for the five suc- cessive breeding seasons of the females (x^g = 24.72, P < 0.01; Fig, 3). In the first and second breeding years, nest sites were chosen mainly be- tween 300-500 m elevation, and a high proportion of the owls nested above the 500 m, but in third, fourth, and fifth breeding seasons the majority of the females nested below 300 m. The increase in the proportion of breeders in the lowest altitude range was greatest between second and third breeding years of the females, and the highest pro- portion was recorded in fourth breeding season (X^g - 24.38, P< 0.001). The movement between the altitude ranges was related to snow conditions and the age of breeding females (Table 3). A large number of females changed elevation in their second breeding year in relation to the previous breeding season, but only a few females did so if there was no snow cover in the early breeding season (x^i — 6.31, P < 0.02). Movement of females between the three altitude 30 Sasvari and Hegyi VoL. 39, No. 1 aj) 550 - 525 - 500 - (L> I 475 £ 450 ^425 I 400 375 350 16 28 16 28 18 26 11 15 9 8 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 years in their third breeding season (x^i = 4.08, P < 0.05). However, snow conditions did not influ- ence changes between elevations in the fourth and fifth breeding years (x^i = 0.13 and x^i = 0.15, respectively; P > 0.05). In most cases females moved from higher to lower elevations (25 of 35 changes; 71.4%, xS = 12.91, P< 0.001). Body Mass and Length of Tarsus before Fledg- ing. Mean body mass and mean tarsal length per brood of the nestlings before fledging increased in subsequent breeding years = 3.69, P — 0.005; /q 170 — 2.87, P — 0.021; respectively; Fig. 4), but differences were not recorded between the third and fifth breeding seasons (F2 84 = 3.01, P = 0.069 and F284 = 3.09, P — 0.062; respectively). Nestlings were heavier with longer tarsal length in years without snow cover than in snow years in the females’ first (^43 = 2.46, P< 0.02; ^43 = 3.88, P< 0.001; respectively) and second breeding years (^43 — 2.33, P < 0.05; ^43 — 4.04, P < 0.001; respec- tively). In the females’ third, fourth, and fifth breeding years, nestlings did not differ either in body mass or tarsal length according to snow con- dition (£13 — 1.59, ^5 = 2.17, £ig = 1.19; P> 0.05 in all occasions). Discussion Hatching Success Versus Fledging Success. The relatively low fecundity of young females compared to older females has been documented both in pas- serines (Perrins 1979, Dhondt 1989) and non-pas- serines (Newton 1989, Saether 1990, Sydeman et al. 1991). Thus, the small clutch size with low hatching success of Tawny Owl females may also be due to low fecundity in their first and second breeding years. Male owls feed their mates during the incubation period, but egg survival was not in- fluenced by male age. Nevertheless, in the females’ first and second breeding years the reduction in number of offspring occurred in the incubation period rather than the nestling period because fledgling success was higher than hatching success. For birds with more breeding experience, during their third, fourth, and fifth breeding years, the relationship between hatching success and fledg- ing success was reversed: lower fledging success 31 March 2005 Tawny Owl Breeding Experience (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 changed or retained nest sites between the three altitude ranges (<300 m, 300-500 m, >500 m) in relation to snow cover and successive breeding seasons. The changes and retentions are related to the nest sites in previous breeding season. The number of pairs are presented in parentheses. Breeding Year of Females Snow Cover Nest Site Changed Nest Site Retained Second Yes 43.8 (7) 53.3 (9) No 10.7 (3) 89.3 (25) Third Yes 61.1 (11) 38.9 (7) No 19.2 (5) 80.8 (21) Fourth Yes 18.2 (2) 81.8 (9) No 13.3 (2) 86.7 (13) Fifth Yes 33.3 (3) 66.7 (6) No 25.0 (2) 75.0 (6) limited the number of offspring produced rather than hatching success. Both females and nestlings depend upon food supplied by the males during the brooding period, thus the differences in fledging success and num- ber of fledglings probably reflected male age. Compared to pairs where the males were the same age or younger than their mates, pairs where the males were older than the females raised more off- spring with higher fledging success. Longitudinal studies on bird species have shown that clutch size and fledging success increased with age to a plateau and decreased among the oldest breeders (Newton et al. 1983, Thomas 1983, Nisbet et al. 1984, Newton 1989, Pugesek and Wood 1992). We have not yet conducted the prolonged studies of the Tawny Owl that would allow us to examine the possible effects of senescence. Nev- ertheless, we believe that the present study was long enough to demonstrate that the females reached a plateau in their breeding success, be- cause females showed no differences in reproduc- tive performances after their third breeding years. Numerical Responses of Tawny Owls to Snow Cover. Predators may respond to fluctuations in the abundance of prey in different ways (Solomon 1949). Numerical responses involve changes in re- productive success, survival, and immigration/ em- igration rate, whereas functional responses reflect changes in prey composition (Andersson and Er- linge 1977). Long-term studies on nocturnal rap- 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 boreal and temperate regions in northern latitudes (Southern and Lowe 1868, Adamcik et al. 1978, 1979, Korpimaki 1986, 1987, Pietiainen et al. 1986, Korpimaki and Norrdahl 1991). The reproductive performance of Tawny Owls increased with increas- ing breeding experience, but the change in pro- ductivity also reflected numerical responses of owls to snow cover. We found that even pairs with considerable breeding experience achieved lower reproductive success in adverse weather conditions with snow cover. Analysis of diet showed that, when the avail- ability of small mammals was low because of snow cover, the males delivered more birds to females and their offspring (Sasvari et al. 2000), and older males were better than young males at providing alternative prey. However, we suggest that in snow years both the young and old males delivered fewer food items with lower total food mass than in years without snow cover and neither the inexperienced nor experienced males were able to compensate fully for the loss of the primary prey. We found lower fledging success in snow years than in years without snow cover even in fourth and fifth breed- ing seasons of the parents. Higher Mass Loss for Females than Males in Years with Snow Cover. When the snow effects re- sulted in a change in prey availability, inexperi- enced parents suffered not only a greater reduc- tion in breeding performance, but also a larger decline in body condition. Reflecting the depen- dence of the females on food supplied by the males during the incubation and brooding period, the differences in the mass between the snow years and years without snow cover were considerably higher for females than males. Hence, we suggest that male owls reduce prey provided to their mates during incubation and early nestling period to en- sure their own survival. In successive breeding years increased breeding experience meant that the males were better equipped to exploit the sec- ondary food resources in adverse weather condi- tions and did not suffer loss of mass. Nest Site Switching by Experienced Breeding Pairs. The Tawny Owl parents shifted nest sites and relocated to new breeding territories at lower ele- vations in snow years. As a consequence of these changes, the majority of parents in their third breeding season and following years nested at low elevations. We suggest that leaving the higher ele- vations and the apparent benefit for older parents of moving, in terms of their increased reproductive performance, is due to the higher frequency of sec- ondary prey available at lower elevations during ad- verse-weather periods. In our previous study on the effect of Tawny Owls’ predation on songbirds (Sasvari and Hegyi 1998), we estimated the abundance of birds around the owl nests in snow years (1993 and 1996) and in years without snow cover (1995 and 1997) . We recorded number of birds over a period of 30 min in a radius of 150—200 m of the nests during the incubation period. The surveys were carried at low, middle, and high altitude ranges between 130—680 m at 24, 31, and 29 sites in snow years and 33, 38 and 32 sites in years without snow cover. The mean number of birds recorded from the low to high altitude range was 15.3 ± 8.7, 9.5 ± 7.6, and 3.4 ± 3.2 = 5.91, P = 0.004) in snow years, and 13.6 ± 6.0, 11.7 ± 5.1, and 8.6 ± 4.7 (E’gaoo ~ 3.86, P — 0.027) in years without snow cover. These data show that possible prey species of birds were most abundant at low elevations in all years, but their numbers were highest at the lowest altitude range in years with snow, when numbers were noticeably reduced at the highest altitude range. The birds, both the prey and predators, were more protected from the effect of adverse weather in valleys than on the steep slopes of the hills. Also, villages and other man-made objects are found in valleys and the birds may also be able to find food related from human activity to aid winter survival. Lower Body Mass and Tarsal Length and Differ- ential Gender Surviv2il. In terms of sexual dimor- phism in raptors, dimorphism in size and body mass is nearly as pronounced at the time of fledg- ing, as in adulthood (Newton and Marquiss 1979, Fiala 1981, Richter 1983, Bortolotti 1986). Adult female Tawny Owls were heavier and larger than the adult males, hence the differences in body mass and tarsal length measured on nestlings, be- fore fledging, reflected the sexual dimorphism of offspring. If one sex requires more food than the other, this sex should experience increased mor- tality when food resources are scarce, skewing the sex ratio toward the less costly sex (Slagsvold 1990, Weatherhead and Teather 1991, Glutton-Brock 1991). We did not identify the sex of the owlets, but on the basis of body mass and tarsal length, we presumed that the sex ratio in the broods of Tawny Owls was biased in favor of the “cheaper” male during difficult feeding conditions. 34 Sasvari and Hegyi VoL. 39, No. 1 The lower mean body mass and mean shorter tarsi of the nestlings in a brood raised in snow years may be due to the shortage of food and the better survival of the sex requiring less investment. Nevertheless, we found no differences in body mass and length of tarsus of nestlings before fledg- ing related to snow cover in the third, fourth, and fifth breeding seasons. The condition of fledglings raised in these years did not differ between the successive seasons. The influence of snow cover on fledglings’ condition was not apparent in the broods of experienced parents. Acknowledgments We are indebted to Fred Gehlbach and anonymous ref- erees for their constructive comments and suggestions. 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Williams, G.C. 1966. Natural selection, the cost of repro- duction, and a refinement of Lack’s Principle. Am. Nat. 100:687-690. Received 12 February 2004; accepted 5 December 2004 J. Raptor Res. 39 ( 1 ) : 36-54 © 2005 The Raptor Research Foundation, Inc. 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 a relatively rich avian diversity in Europe. Despite recognized importance of the country in support- ing a significant biodiversity, mapping of the avi- fauna has not occurred and there are few data on the status of birds in Turkey. Among the birds of Turkey are included 40 di- urnal birds of prey and 10 owls. For Europe and the Middle East, Forsman (1998) lists 42 raptors, Glutz et al. (1987) list 41, and Gensbol (1986) lists 46 species. Weick (1980) and Kiziroglu et al. (1993) reported 39 diurnal raptors in Turkey. This was increased to 40 with the addition of the Bar- bary Falcon (Falco pelegrinoides; Kirwan et al. 1998) . However, the number of the studies on raptors in Turkey is minimal and little is known about their distribution. Kumerloeve (1970) provided the first significant contribution on the status and distri- bution of raptors in Turkey. The initial focus of research on raptors in Turkey was migration. Al- though the number of studies in eastern Europe examining birds have increased recently, there are still little data and information available on the size of raptor populations and their conservation. Here, I present a summary of species-specific ob- ^ Email address: letur@hacettepe.edu.tr servations of diurnal raptors collected during 2001-02 from locations throughout Turkey. Methods Turkey is divided into seven geographical regions (Eig. 1; Erol et al. 1982) characterized by variable landscape types, climate differences, and a rich diversity of fauna Field data were obtained from surveys conducted in all areas of Turkey between 1 January 2001-31 December 2002. Many observations were based on a combination of the field surveys and data from birdwatchers and oth- ers (Toygar 2001, 2002). The remaining observations were gathered from the trip reports of visiting ornithol- ogists in Turkey (Balmer and Betton 2001, Comas et al. 2001, Dyczkowski 2001, Merril 2001, Swann 2001, Balmer and Betton 2002, Eriksen and Eriksen 2002, Giannatos, 2002, Klim 2002). The methodology used was derived from standardized bird-survey techniques (Bibby et al. 1998), and from tran- sect counts (Bibby et al. 2000). Daily surveys were con- ducted in the middle of the day from 0900-1300 H at 134 selected localities within 43 of 81 provinces in 2001, and 197 localities within 54 provinces in 2002. Observa- tion grids were used to evaluate all observations and rec- ords (Fig. 1; Appendix). During the observations, 162 line transects were used to assess nonbreeding raptor populations over extensive areas. The mean distance of transects was 5098 m. Most of the observations were made by teams of one to three 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 raptor species. The mean spot counts per survey was 1.47. 36 March 2005 Status of Diurnal Raptors in Turkey 37 1 2 3 4 5 6 7 8 9 10 11 12 13 U 15 16 17 18 19 Spot counts were conducted during selected stops at lo- cations with a good view. A single observer systematically scanned the sky for 5 min and counted all raptors visible with the naked eye. The coordinates of spot counts were recorded with a Global Positioning Receiver System and binoculars were used to aid in the identification of the species. Definitions used to describe the status of birds in Tur- key are as follows (Weaver 1981, Kiziroglu 1989): Resident A bird that is present all year and breeds regu- larly. Summer visitor. A bird that uses a particular area for breed- ing only and is not present outside the breeding season. Winter visitor. A bird that visits a particular area only dur- ing the winter and does not occur there during its breed- ing period. Migrant A bird that occurs irregularly and may be seen on migration, sometimes in great numbers. Vagrant A bird for which there are only one or a few records a year in Turkey. Results and Discussion Assistants and I recorded diurnal raptors at 134 sites during 324 observation periods in the year 2001, and 197 sites during 416 observations in the year 2002. The data collected during 2001 and 2002 were compatible with each other to a great extent in terms of effort and number of raptors recorded. Observations of the individual species were as follows; Most Frequently Observed Raptors. European Honey-buzzard {Pernis apivorus) . The honey buzzard is a summer visitor and migrant. It was seen during 15 surveys between March-September 2001, in- cluding one observation of 550 migrants in Istan- bul (Marmara region) on 2001. It was also seen 15 times during surveys between April-November 2002, but none were recorded in July. Black Kite {Milvus migrans). This resident raptor species was seen on 16 surveys, during all the months of 2001 with the exception of February. One unexpected observation occurred in south- east Anatolia (Gaziantep Province), registered in December and involved 400 individuals (Demircan 2001). In 2002, Black Kite was observed 17 times between April-September, with no records noted in July. According to Clark (1999) Black Kites are local summer breeders throughout most of Eu- rope. Most Black Kites leave Europe for winter, but some stay in Turkey and in the Middle East. White-tailed Eagle {Haliaeetus albicilla). Fairly com- mon resident and winter visitor, the White-tailed Eagle was recorded five times during 5 mo in 2001 and eight times in January, April, May, and Decem- ber in 2002. White-tailed Eagles in Turkey are from the southeastern European population. The indi- viduals of this population were smaller and have lighter-colored heads. They mostly reside in Cau- casus, Greece, and in parts of Bulgaria. In Turkey, this species generally lives near inland seas, where- as in northern Europe, this bird occurs in coastal plains. The population in Turkey was estimated at no more than 100 pairs (Vaassen 2001). Most of the individuals of this species have short migratory ranges. Egyptian Vulture {Neophron percnopterus) . The 38 Turan VoL. 39, No. 1 Egyptian Vulture is one of the four vulture species that is widespread in Turkey. A summer visitor and rare transient, the Egyptian Vulture was seen on 13 surveys every month between March-September 2001 and 19 times between March-September 2002, with the exception of August. Cinereous Vulture {Aegypius monachus). This resi- dent raptor species is the largest bird of prey in Turkey. It was observed 10 times during 4 mo be- tween March-October in 2001. It was seen six times between February-November 2002, with the exception of May, July, and August. Short-toed Snake-Eagle ( Circaetus gallicus) . An abun- dant summer visitor and migrant species, the Short-toed Snake-Eagle was seen on 23 occasions and during every month between February-Octo- ber 2001. During two surveys in September, 25 and 34 migrants were recorded. Also, 39 migrants were recorded during one survey in October 2001. This raptor was recorded 27 times between March-No- vember 2002, with the exception of July. Western Marsh Harrier {Circus aeruginosus) . This raptor is the most abundant harrier in Turkey. The Marsh Harrier is a resident, partial migrant, and winter visitor. Although Clark (1999) mentioned that it was rare and local, I found that these har- riers were abundant. It was seen 76 times through- out 2001 and 109 times in every month of 2002. Northern Harrier ( Circus cyaneus) . Although a very common winter visitor and migrant, the Northern Harrier was very rare in summer. I recorded it on 37 occasions between September-April 2001, 57 times and during every month of 2002, with the exception of June-August. Montagu’s Harrier {Circus pygargus). A summer visitor and migrant, Montagu’s Harrier was seen 15 times in every month of 2001, with the exception of May, June, October, and December. This harrier was observed on 11 occasions in 2002 between April-October, with the exception of May and July. Northern Goshawk {Accipiter gentilis) . This uncom- mon resident was seen on 10 occasions in 7 mo of 2001, and six times in 5 mo of 2002. Eurasian Sparrowhawk {Accipiter nisus). A com- mon resident and very common migrant in Turkey. This species was recorded 58 times in 2001 and 54 times during every month in 2002. Levant Sparrowhawk {Accipiter brevipes). The Le- vant Sparrowhawk was a summer visitor and mi- grant species. During one survey in September 2001, 68 migrants were recorded. However, it was observed only on five occasions in September 2002 . Common Buzzard {Buteo buteo). A common, wide- spread resident and migrant, the Common Buz- zard was the second most frequently recorded rap- tor (100 observations) in 2001. During one survey in September 2001, 640 migrants were recorded. The Common Buzzard was the most commonly-ob- served raptor species {N — 121) in 2002. Long-legged Buzzard {Buteo rufinus). A very com- mon resident and abundant winter visitor, the Long-legged Buzzard was generally seen in semi- arid and mountainous areas. It was the most fre- quently recorded raptor species {N = 109) in 2001, and the second most frequently recorded raptor {N= 115) in 2002. Lesser Spotted Eagle {Aquila pomarina) . The Lesser Spotted Eagle is a common migrant and scarce summer visitor of forests with bordering plains throughout Turkey. It was recorded on 22 occa- sions in 9 mo. In 2001, 3424 migrants were record- ed during one survey in September and 130 mi- grants during a survey in October. It was also seen 15 times in 2002 between April-October, with the exception of July. Greater Spotted Eagle {Aquila clanga) . A winter vis- itor and partial migrant raptor. It was recorded eight times in 2001 and nine times in 2002. Imperial Eagle {Aquila heliaca) . The Imperial Ea- gle is a rare resident, winter visitor, and migrant in Turkey. It was observed in small numbers in 2001 and on 12 occasions between February-August 2002. The Imperial Eagle has been classified as a globally-threatened species (Collar et al. 1994), and breeding populations have declined through- * out southern Europe, North Africa, and the Mid- dle East (Cramp and Simmons 1980, Biber 1990, Clark 1999). Golden Eagle {Aquila chrysaetos). The most wide- spread resident eagle species in Turkey, the Gold- en Eagle was seen on 18 occasions in 8 mo of 2001 and 15 times in different regions in 2002, with the exception of August and September. Even though Vaassen (2001) suggested that Golden Eagles were the most common Aquila in Turkey (2000-3000 pairs) , there were no Golden Eagles sighted in Feb- ruary, April, August, and December in 2001. Booted Eagle {Hieraaetus pennatus). The Booted Eagle is a common summer visitor and migrant. It breeds in forests with a mixture of open ground in 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 and 15 times during 6 mo of 2002. Bonelli ’s Eagle (Hieraaetus fasciatus) . A rarely seen resident species, Bonelli’s Eagles were recorded five times during 4 mo of 2001, and five times dur- ing 5 mo of 2002. European populations of this species have experienced a marked decline and this raptor is considered a vulnerable species (Ro- camora 1994, Clark 1999). Real et al. (1996) esti- mated that a peripheral, sedentary population with ca. 1000 pairs inhabits the Mediterranean area of Europe. Osprey {Pandion haliaetus). The Osprey is a rare summer visitor and migrant raptor. Ospreys were recorded seven times in February, March, August, September, and November 2001, and four times in 4 mo of 2002. The Osprey has historically bred in the Marmara and Black Sea regions (Vaassen 2001). However, even though they were observed, they have not been found breeding recently in that region (Vaassen 2001). Lesser Kestrel {Falco naumannt). The Lesser Kes- trel is a small colonially-nesting falcon distributed throughout Turkey. It is present in the summer and is a rare winter visitor that mostly winters in Africa and south of the Sahara Desert (Cramp and Simmons 1980, Clark 1999). This species was ob- served nine times between March-October. During two surveys in August 2001, 70 and 10 migrants were recorded, respectively, and 25 migrants were recorded during one survey in September. In 2002, it was observed on 23 occasions in every month, with the exception of September. The Lesser Kes- trel was previously considered as one of the most abundant raptors in Europe (Bijleveld 1974), but it has recently become extinct in several countries (Biber 1990). Parr and Yarar (1993) stated that the population of Lesser Kestrels in Turkey was 1500- 3500 pairs, ranking as the second-largest popula- tion in the world. Eurasian Kestrel {Falco tinnunculus) . The Eurasian Kestrel is the most widespread resident falcon spe- cies in Turkey. This falcon was found mostly in open country, on plains, and arable fields. They were also common in urban habitat. It was ob- served on 98 occasions in 2001 and 97 times in 2002. Red-footed Falcon {Falco vespertinus) . The Red-foot- ed Falcon is a migrant and rare summer visitor in Turkey. During two surveys in August 2001, 10 and 70 migrants were recorded, respectively. Also 25 migrants were seen during one survey in Septem- ber 2001. This bird was observed on 12 occasions in 2002, outside of the breeding season (May— Au- gust) . Eleonora ’s Falcon {Falco eleonorae) . This raptor spe- cies is a rare summer visitor, but it is widespread in Turkey during migration. The Eleonora’s Falcon was observed on six occasions in 2001 and only twice in 2002. Merlin {Falco columbarius) . The Merlin is a fairly common winter visitor and migrant found throughout the country. Merlins from central Asia also winter in Turkey (Clark 1999). In 2001, it was observed on nine occasions during January, Feb- ruary, April, and December 2001, and 13 times during January, April, May, September, and Octo- ber of 2002. However, no evidence of breeding was recorded. Eurasian Hobby {Falco subbuteo) . A common sum- mer visitor, the hobby breeds in a variety of habi- tats. It was observed on 22 occasions, between April-October 2001, and 22 times between April- October 2002, with the exception of July. Peregrine Falcon {Falco peregrinus) . The Peregrine Falcon is a fairly common summer visitor and res- ident. This large falcon was seen on 20 occasions during 11 mo of 2001, with the exception of May. It was also seen 27 times in 9 mo of 2002, with the exception of May, September, and October. Clark (1999) stated that most populations of peregrines had a marked decline between 1950-70 due to var- ious persistent pesticides. Infrequently-detected Species. The Red Kite {Milvus milvus) and Rough-legged Hawk {Buteo la- gopus) were recorded only once in both 2001 and 2002. The Pallid Harrier {Circus macrourus) and Steppe Eagle {Aquila nipalensis) were recorded only once in 2001, and four times in 2002. Both species only migrate through Turkey. However, sporadic breeding records of Pallid Harrier in Turkey have been recorded (Clark 1999). Turkey is the primary geographic region supporting Bearded Vultures {Gypaetus barbatus) in Europe and the Middle East. It is widespread across Turkey into the Caucasus (Clark 1999) and a very rare and local resident in high mountains; however, its numbers are declin- ing. Svennson et al. (1999) estimated that there were only 500 pairs left within this region. Bearded Vulture was recorded only once in 2001, and five times in 2002. The Eurasian Griffon {Gyps fulvus) is primarily a resident in the mountains of the Mediterranean area, particularly in Turkey. Breed- ing griffons in most of Turkey are migratory and 40 Turan VoL. 39, No. 1 leave in winter (Clark 1999). The population in the western half of the country has undergone a sig- nificant decline (Kasparek 1992). Griffons were seen on five occasions in 2002. The Sooty Falcon {Falco concolor) was recorded on two occasions in 2001 and not seen in 2002. Tanner Falcons {Falco biarmicus) and Saker Falcons {Falco cherrug) were seen on 2-5 occasions both in 2001 and 2002. The last species was observed only once in 2002. Species Not Recorded in 2001 and 2002. The Barbary Falcon {Falco pekgrinoides) was not ob- served in either 2001 or 2002. This species was seen in Birecik, southeastern Anatolia in 1990-94, but has not been observed since. Therefore, I clas- sify it as a “vagrant.” The Oriental Honey-buzzard {Pernis ptilorhynchus) , and Black-winged Kite {Elan- us caeruleus) are very rare raptor species. They were not sighted in 2001 or 2002. Due to their position on top of the food chain, diurnal raptors occur in relatively small numbers and, therefore, are more subject to declines or ex- tinctions than other birds. The problems facing raptors in Turkey are similar to that elsewhere. Ag- ricultural insecticides are still responsible for the decline of some raptor populations in Turkey (Vaassen 2001). In addition, sparrowhawks are hunted in northeastern Turkey (Turan 1986). Though not very common, I have documented that some raptors were captured for falconry. Oc- casionally, a large sum will be paid in the Middle East for a bird trained for falconry (Turan 1986). Although the Turkish government has initiated an intensive hunter-training program, there still exists a problem of illegal hunting. This study summarizes data obtained from field surveys carried out in different regions of Turkey over a 2-yr period. No comparable data from pre- vious years were available. For this reason, I urge that future surveys be conducted to track the change of raptor populations in Turkey. Acknowledgments I want to thank the many volunteer birders who con- tributed to this list. I am very grateful to W. Mahoney and I. Ozyildirim for improving the English of this paper, also to the anonymous referees for their valuable com- ments on earlier drafts. Literature Cited Balmer, D. and K. Betton. 2001. Around the region 2001 Turkey. Sandgrouse2^:15&. AND . 2002. Around the region 2002 Tur- key. Sandgrouse Bibby, C., M. Jones, and S. Marsden. 1998. 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Important records on Black Kte Mtl- vus migrans. Ibibik 1:1—29. Dyczkowski, J. 2001. Trip reports, Turkey, http:// www.osme.org/ osmetrip/turkl 5.html. Eriksen, H. and J. Eriksen. 2002. Trip reports, Turkey http://www.osme.org/ osmetrip/ turk21.html. Erol, E., V. Stohr, and W. Denk. 1982. Die naturraum- liche Gliederung der Tiirkei. Karte 1: 2000000. Tiib- inger Atlas des Vorderen Orients, Blatt A VII 2. Univ. Tubingen, Tubingen, Germany. Forsman, D. 1998. The raptors of Europe and the Middle East: a handbook of field identification. T. & A.D. Poy- ser, Calton, U.K. Gensbol, B. 1986. Collins guide to the birds of prey of Britain and Europe, North Africa, and the Middle East. Collins Press, London, U.K. Giannatos, G. 2002. Trip reports, Turkey, http:/ / www.osme.org/osmetrip/turkl7.html. Glutz, U.N., K.M. Bauer, and E. Bezzel. 1987. Hand- buch der Vogel Mitteleuropas. Aula, Wiesbaden, Ger- many. Kasparek, M. 1992. Die Vogel der Tiirkei: eine ubersicht. Kasparek Verlag, Heidelberg, Germany. Krwan, G.M., R.P. Martins, G. Eken, and P. Davidson 1998. Checklist of the birds of Turkey. Sandgrouse 1 1-32. Kziroglu, I. 1989. Tiirkiye Ku§lari. Desen Ofset, Ankara, Turkey. , L. Turan, and A. Erdogan. 1993. Ein Beitrag zur Tiirkischen Greifvogelfauna und ihrer Gefahrdungs- grade. H. U. Egit. Fak. Derg. 9:271-279. Ktm, R. 2002. Trip reports, Turkey, http://www.osme. org/osmetrip/ turk20.html. Kumerloeve, H. 1970. Zur kenntnis der Avifauna der March 2005 Status of Diurnal Raptors in Turkey 41 Kleinasiens und der Europaeischen Tiirkei. Istanbul. Tip. Fak. Mecm. 35:85-160. Merril, I. 2001. Trip reports, Turkey, http://www.osme. org/osmetrip/ turkl6.html. Parr, S. and M. Yarar. 1993. Preliminary results from a Lesser Kestrel survey of Turkey, spring 1993. Ornithol. Soc. Middle East Bull. 31:8—10. Real, J., S. Manosa, and J. Godina. 1996. Estatus, de- mografia y conservacion del aquila perdicera en el Mediterraneo. Pages 83-90 inj. Muntaner and J. May- ol [Eds.], Biologia y conservacion de las rapaces Med- iterraneas, 1994. BirdLife International, Madrid, Spain. Rocamora, G. 1994. Bonelli’s Eagle {Hieraaetusfasciatus). Pages 184-185 in G.M. Tucker and M.F. Heath [Eds.], Birds in Europe: their conservation status. BirdLife International, Cambridge, U.K. Swann, B. 2001. Trip reports, Turkey, http://www.osme. org/osmetrip/turkl4.html. SVENNSON, L., P.J. Grant, K. Mullarney, and D. Zetter- STROM. 1999. Collins bird guide. Harper Collins Pub- lishers, London, U.K. Toygar e-group. 2001. Recent records in Toygar e-group on the bird species in Turkey, http://groups.yahoo. com/ group/ toygar. . 2002. Recent records in Toygar e-group on the bird species in Turkey, http:/ /groups.yahoo.com/ group/ toygar. Turan, L. 1986. Hunting with using of the birds of prey in Turkey./. Fac. Educ. 12:207-210. Vaassen, E.W. 2001. Recent status of birds of prey in Tur- key. Poster at 4* Eurasian Congress on Raptors, 25- 29 September 2001, Seville, Spain, Weaver, P. 1981. The birdwatcher’s dictionary. T. 8c A.D. Poyser Ltd., Cambridge, U.K. Weick, F. 1980. Greifvogel der Welt. P. Parey, Hamburg, Germany. Received 28 July 2003; accepted 14 November 2004 Turan 42 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. Province / District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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 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. Province/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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 An kara-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. Provinge/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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 dir n e-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. Province/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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. Province/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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-S akliken 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 N igde-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. Province/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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 kar a-N allih 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. PROVINCFyDiSTRICT Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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. Province /District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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. Province/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Ttpe Transect Distance (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 Edir n e-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-N allihan 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. Province/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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. Province/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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. Province/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number of Raptors Observa- tion Type Transect Distance (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. Province/District Observa- tion Grid Sampling Date Number OF Spot Counts Number OF Raptor Species Number OF Raptors Observa- tion Type Transect Distance (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 4500 Ardahan-Hanak C17 12 Nov 02 4 4 Line 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 N= 499 X = 1.47 0 0 Spot N= 162 X - 5097 5 Short Communications J Raptor Res. 39(l):55-60 © 2005 The Raptor Research Foundation, Inc. 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- cultural areas; Chile. The Aplomado Falcon (Falco femoralis) is distributed from southwestern United States to Tierra del Fuego Isla Grande in southern Argentina and Chile. Aplomados in- habit open areas such as savannas, desert grasslands, An- dean and Patagonian steppes, and tree-lined pastures, from coastal plains up to 4000 m in the Andes (Brown and Amadon 1968, de la Pena and Rumboll 1998). In the United States, the Aplomado Falcon is listed as en- dangered (Shull 1986) due to the historical modification of its habitats and cumulative effects of DDT (Kiff et al. 1980, Hector 1987). In contrast, the Chilean population may be increasing. Forest conversion to agricultural lands have increased hunting habitat and prey availability for this species (Jaksic and Jimenez 1986). Nonetheless, the Aplomado Falcon is rare in southern Chile (Jaksic and Jimenez 1986) and it is protected legally (Republica de Chile 1996, 1998). The biology of the Aplomado Falcon is little known. Breeding biology, survival, movements, and habitat use have recently been reported (Perez et al. 1996, Montoya et al. 1997). Studies on Aplomado Falcon summer diet have been conducted in northern Mexico (Hector 1981, 1985), northern Chile (Jimenez 1993), and southeastern Argentina (Bo 1999). Some recent anecdotal descrip- tions of predation on crayfish (Combarus diogenes; Clark et al. 1989), Spotted Tinamous (Nothura maculosa; Silveira et al. 1997), and lizards (Liolaemus lineomaculatus; Trejo et al. 2003) have also been published. Piracy also has been documented as an important foraging method for obtaining mammal prey from other raptors (Brown et al. 2003). However, seasonal differences in diet have not been described. Here, we report the seasonal diet of Aplomado Falcons and correlate it with prey abundance in the Araucanian agricultural area in southern Chile. Study Area and Methods Our study area was the Tricauco Farm (200 ha), 6 km south of Traiguen city (38°14'S, 72°38'W) in the Arau- ^ Email address: asio@surnet.cl cania region, southern Chile. The landscape is com- prised mainly of wheat and oat crops, scattered pasture and sedge-rush (Carex-Juncus spp.) marshes, small plan- tations of nonnative Pinus spp. and Eucalyptus spp., and remnants of the native southern beech (Nothofagus spp.) forest. The climate is moist-temperate with a Mediterra- nean influence (di Castri and Hajek 1976). Mean annual rainfall and temperature are 1400 mm and 12°C, respec- tively. From August (austral winter) to December (austral spring-summer) 1997, we collected 65 pellets under trees and fence posts used as pluck sites by at least one pair of Aplomado Falcons. We collected 40 pellets during winter and 25 during spring-summer. A few prey remains were also collected beneath pluck sites during the spring-summer period. Although pellets could be con- fused with those of the sympatric Cinereous Harrier (Cir- cus cinereus) or American Kestrel (Falco sparverius), we only saw Aplomado Falcons at the collection sites during our study. Perches identified as those of Cinereous Har- riers and American Kestrels were located away from (1.0- 1.5 km) known Aplomado Falcon pluck sites. In addition, Aplomado Falcons are aggressive toward other raptors (Hector 2000, Brown et al. 2003). Avian prey were identified mainly on the basis of feath- ers, using two complementary methods: microscopic analysis of feather structures such as nodes and barbules (Reyes 1992), and a comparison of feather coloration patterns with voucher specimens deposited in the Zool- ogy Department of the Universidad Austral of Chile at Valdivia. We assumed that species identified in a pellet represented only one individual. Small mammals were identified and quantified on the basis of skulls or denti- tion following Pearson (1995). Insects were identified and quantified by head capsules or elytra following Pena (1986). We identified prey items to the finest possible taxonomic category. Biomass contribution was estimated following Marti (1987). Masses for small mammal and avian prey followed Figueroa and Corales (1999). Insect masses were based on the authors’ unpublished data. We assumed that unidentified prey masses were similar to the mean mass of the most closely related identified taxon. Concurrent to the collection of pellets, we evaluated bird and small mammal prey abundance in the field. We estimated bird abundance using parallel, fixed-band (2000 m long, 100 m wide) line transects (Bibby et al. 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. Prey Species Mass'^ (g) Diet'^ Winter Spring-Summer Annual Percent Frequen- cy Percent Biomass Percent Frequen- cy Percent Biomass Percent Frequen- cy Percent 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 Ant bus 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 three during spring-summer. The abundance of small mammals was evaluated by trapping transects (Call 1986) using medium Sherman live traps (10-15 m apart) placed in unaltered pasture and marshes. Three 10-trap transects were established in pasture during winter and three in pasture and two in marshes during spring-sum- mer, and these were sampled for 5 nights. Thus, total effort was 351 trap-nights (nonfunctional traps were dis- counted) . Seasonal changes between proportions in different prey taxa in diet were evaluated with chi-square tests us- ing contingency tables (Fowler and Cohen 1986). Only vertebrate prey were included for analysis; contribution of insects was insignihcant. Geometric mean weight of prey (Marti 1987) was calculated as follows: GMW = an- tilog (Sn^logtc/Snj), where was the number of individ- uals of the ith species and w, was the mean weight. Only prey items identified to species level were included to estimate GMW. Differences among GMW were analyzed using t-tests (Fowler and Cohen 1986). To determine whether falcons took vertebrate prey selectively or op- portunistically, we compared frequency distribution of prey in pellets versus prey abundance in the field using Spearman’s rank correlation as recommended by Jaksic (1979) for a comparison between prey consumption and availability. Because of the small sample size for each sea- son, we combined results of the winter and spring-sum- mer diet for correlations. Results Whole pellets averaged 27.3 ±1.3 mm length X 13.3 ± 0.5 mm width and had a mean dry weight of 0.9 ± 0.08 g (x ± SE, N = 36). In total, we identihed 115 prey items in the pellets including seven bird species, three rodent species, and three insect orders (Table 1 ) . By both 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 group of birds most frequently found in pellets, with Aus- tral Thrushes {Turdus falcklandii) and Grassland Yellow- Finches {Sicalis luteiventris) being the most common prey species (Table 1). By biomass, the Austral Thrush and Eared Dove {Zenaida auriculata) were the most important avian prey both during winter and spring-summer. Ro- dents were an important part of the winter and overall diet with olivaceus field mice {Abrothrix olivaceus) being the most frequent (Table 1). Insects were negligible both by number and biomass. Because of small sample size and uncertainty as to how much of each item was consumed, we did not use prey remains to quantify diet. However, feather remains con- firmed that the Austral Thrush and Eared Dove were the most common prey of the Aplomado Falcon. In addition, we found elytra {N = 40) of the cerambycid Acanthinodera cummingi indicating 20 individuals. More birds and less rodents were consumed during spring-summer as compared to the winter season (x^ = 17.4, P < 0.001; Table 1). Proportions of Columbiformes and Passeriformes remained similar between seasons (x^ = 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 ± 14.2 g for birds alone. No seasonal differences were de- tected in GMW for all prey combined (48.3 ± 6.1 g for winter and 37.0 ± 5.5 g for spring-summer; ^ = —1.3, P > 0.05) or for vertebrate prey (48.3 ± 6.1 g for winter and 58.8 ± 5.6 g for spring-summer; % = 0.6, P> 0.05). For the year, we counted 1782 non-raptor birds com- prising 33 species. The most numerous species were the Grassland Yellow-Finch, Southern Lapwing {Vanellus chi- femw) , Austral Thrush and Rufous-collared Sparrow {Zon- otrichia capensis-. Table 2) - More birds were observed dur- ing winter (993 birds/km^) than spring-summer (482 birds/km^). We captured 43 rodents comprising seven species. By number, the most abundant species were the olivaceus field mouse, long-tailed rice rat {Oligoryzomys longicaudatus) , and house mouse {Mus domesticus-. Fig. 1). Rodent captures declined from winter (22 rodents/100 trap nights) to spring-summer (5 rodents/ 100 trap nights). Only 21.2% of the potential bird prey were found in the pellets (7 out of 33). Spearman rank correlation was = 0.42 (P < 0.05, N = 33) when all bird prey were considered; and r^ = 0.72 (P < 0.01, N = 19) when pas- serines alone were considered. Although we made no sta- tistical correlation for rodents because low numbers of species were identified in the diet, their proportions were in close agreement with those observed in the field (Fig. 1 ). Discussion As in previous studies (Hector 1985, Jimenez 1993, Montoya et al. 1997, B6 1999), the Aplomado Falcon in Tricauco was essentially an avian predator. Our study was most comparable to Hector (1985) and B6 (1999) be- cause it was also conducted in agricultural areas. Similar to our results, both of these studies found that during the breeding season passerines and doves were the most 58 Short Communications VoL. 39, No. 1 50 Aoli Olon Mdom Alon Rnor Lmic Pdar Species Figure 1. Comparison between the proportion of ro- dent prey in the Aplomado Falcon’s diet versus the rel- ative abundance in the field estimated by live-trapping during 1997 in an agricultural field in Tricauco, Arau- canfa region, southern Chile. Graph shows the pooled results of the winter and spring— summer diet and field trapping. Aoli = Abrothrix olivaceus, Olon = Oligoryzomys longicaudatus, Mdom = Mus domesticus, Alon = A. longi- ptlis, Rnor = Rattus norvegicus, Lmic = Loxodontomys mi- cropus, Pdar = Phyllotis darwini. important prey for Aplomado Falcons. The small number of bird species observed in the diet in Tricauco com- pared to those observed during surveys in the field (Ta- ble 2) was probably a result of small sample size of pellets analyzed. The importance of birds in the Aplomado Falcon’s diet was seasonally consistent, suggesting that birds are pre- ferred prey in spite of variability in temporal abundance in the field. The seasonal proportion of rodents in the Aplomado Falcon’s diet in Tricauco was in close agree- ment with the results of the rodent trapping (Fig. 1). Murua and Gonzalez (1986) documented a similar oscil- lation for a rodent population in prairie-scrublands of southern Chile. Our data suggests that Aplomado Fal- cons in Tricauco could respond opportunistically to the availability of rodents that varies seasonally. It is possible that some rodent prey were taken by pirating from other raptors, as documented for Aplomado Falcons in south- ern Texas and northern Mexico (Brown et al. 2003), but we did not witness piracy in Tricauco. The GMW of all prey taken during breeding season in Tricauco was greater than those reported by Hector (1981) in Mexico (23.8 g) and Bo (1999) in Argentina (25 g); this result was likely due to the higher incidence of larger prey in our study area. It is also possible that higher GMW for Tricauco was an artifact of the relatively small numbers of pellets collected during spring-sum- mer. In general, our results suggested that Aplomado Fal- cons consumed most of their prey opportunistically rath- er than selectively (i.e., they took prey in proportion to its abundance), especially for passerine birds and ro- dents. 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 sur- veys. 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 dur- ing the winter when cereal seeds were more available (Bucher and Orueta 1977), possibly making this species more vulnerable to predation. In addition, Aplomado Falcons may have captured doves when they were roost- ing in trees (Hector 1986). The Aplomado Falcon’s apparent selection of Eared Doves was further indicated by the fact that no Southern Lapwings (body mass = 270 g) were found in the falcon’s diet. The Southern Lapwing is a conspicuous ground- dwelling bird and was the second most abundant species in the field (356 individuals, 20% in number). We sug- gest that their aggressive defensive behaviour prevented the falcons from preying upon lapwings. When menaced by a potential predator, Southern Lapwings simulate at- tacks by exhibiting their wing-spurs and emitting strident vocalizations (Walters 1990). Regarding passerine prey, the rate of consumption of Austral Thrushes and Grassland Yellow-Finches were con- sistent with their abundance in the field, but was proba- bly accentuated by their conspicuousness. Similar to Eared Doves, both species moved actively in large flocks when searching for food on cultived fields. Although the Grassland Yellow-Finch was the smallest passerine avail- able (16 g), its abundance in open fields may have com- pensated for its small caloric value. Like Jimenez (1993), we found that Aplomado Falcons generally took more seed-eating than insectivorous birds (6:1; see Table 1) Thus, Aplomado Falcons may be less affected by organ- ochlorine pesticides in the agricultural fields of Chile than in Mexico (Kiff et al. 1980). Our examination of other vegetative-cover types sug- gested that agricultural fields offer a wide variety of ap- propriately-sized prey of which Aplomado Falcons can ex- ploit selectively or opportunistically in southern Chile. However, our inferences must be limited because of the small sample size of pellets and the restricted study area considered. More data using appropriate methods to study dietary and foraging habits of Aplomado Falcons should clarify the relationships suggested by our study. DIETA ESTA.SIONAL DE FALCO FEMORALIS EN UN ArEA AgrIcola de Araucania, Sur de Chile Resumen. — La dieta del halcon Falco femoralis fue cuan- tificada sobre la base de 65 regurgitados colectados dur- ante 1997 en un area agricola del sur de Chile. Las aves fueron el nucleo de la dieta (58-88% por numero, 84— March 2005 Short Communications 59 99% por biomasa), siendo Turdus falcklandii, Sicalis luteiv- entris y Zenaida auriculata las presas mas importantes. Los roedores fueron importantes en la dieta invernal (43% por numero, 16% por biomasa), pero disminuyeron no- toriamente en primavera-verano, coincidiendo con la abundancia estacional de roedores en el campo. El peso medio geometrico fue 42.0 ± 9.1 g para todas las presas y 51.8 ± 10.3 g para las presas vertebradas. Estos valores son mas altos a los reportados por otros autores y seria una consecuencia de la mayor incidencia de presas gran- des en nuestra area de estudio. El halcon perdiguero consuraio una importante fraccion de sus aves presa de acuerdo a nuestras estimaciones de abundancia en el campo (r^ = 0.42, P< 0.05). Las tortolas, sin embargo, fueron consumidas en mayor proporcion que los paseri- nos. Esto sugiere que el halcon perdiguero en Tricauco se comportaria como un depredador parcialmente selec- tive. [Traduccion de los autores] Acknowledgments We thank the Zenhder Stappung family for permission to work on their lands and are especially grateful to Olga Stappung for partially funding this study and to Lilian Stappung for logistical support. Roberto Schlatter kindly permitted access to collections in the Departamento de Zoologia de la Universidad Austral in Valdivia. Diane Haughney helped us with the English revision. Cogent and enlightening suggestions by Ana Trejo, David Ellis, Angel Montoya, Michael Goldstein, and an anonymous reviewer helped to improve this paper substantially. This paper is a product of the Wildlife in Agricultural Land- scape project financed by private funds. Literature Cited Bibby, C., N. Burges, and D. Hill. 1993. Bird census techniques. Academic Press, London, U.K. B6, M.S. 1999. Dieta del halcon plomizo {Falco femoralis) en el sudeste de la Provincia de Buenos Aires, Argen- tina. Ornitol. Neotrop. 10:95-99. Brown, L.H. and D. Amadon. 1968. Eagles, hawks, and falcons of the world. Vol. 1. Country Life Books, Lon- don, U.K. Brown, J.L., A.B. Montoya, E.J. Gott, and M. Curtl 2003. Piracy as an important foraging method of Aplomado Falcons in southern Texas and northern Mexico. Wibon Bull. 115:357-359. Bucher, E.H. and A. Orueta. 1977. Ecologia de la re- produccion de la paloma Zenaida auriculata. Ecosur4: 157-185. Call, M. 1986. Rodents and insectivores. Pages 429-452 in A.Y. Cooperrider, R.J. Boyd, and H.R. Stuart [Eds.], Inventory and monitoring of wildlife habitat. U.S. De- partment of the Interior. 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Mesostigmatic Mites (Acari: Mesostigmata) in White-tailed Sea Eagle Nests {Haliaeetus albicilla) DariuszJ, Gwiazdowicz^ Department of Forest 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 91 A, 60-569 Poznan, Poland Tadeusz Mizera Department of Zoology, August Cieszkowski Agricultural University, ul. Wojska Polskiego 71c, 60- 625 Poznan, Poland PlOTR TRYJANOWSKI Department of Behavioural Ecology, Adam Mickiewicz University, ul. Umultowska 89, 61— 614 Poznan, Poland Key Words: White-tailed Sea Eagle, Haliaeetus albicilla; nest biology, mites', Mesostigmata', Poland. Although studies on mites living in bird nests were first carried out 70 yr ago (Nordberg 1936), knowledge on mite communities in this microhabitat is largely inade- quate. Recently, the acarofauna of small passerine nests have been studied including detailed studies on Great Reed Warbler {Acrocephalus arundinaceus ) , Reed Warbler (A. scirpaceus) , Penduline Tit {Remiz pendulinus) , and Red- backed Shrike {Lanius collurio', Masan and Kristofik 1995, Krikofik et al. 2001, Tryjanowski et al. 2001). However, information about mites occurring in bird nests is still fragmentary, especially in reference to the acarofauna of raptor nests (e.g., Philips 1981, 2000, Philips et al. 1983, ^ Email: dagwiazd@au.poznan.pl March 2005 Short Communications 61 Gwiazdowicz et al. 1999, 2000, Gwiazdowicz and Mizera 2002 ). In contrast to passerines, many raptor species use their nests for several successive years, which allow communi- ties of invertebrates to develop. In addition, the relatively long period over which raptor nests are used allows for temporal changes in acarofauna composition and popu- lation dynamics to be observed. Here, we compared the composition of the mite community of the order Meso- stigmata occurring in two different nests of White-tailed Sea Eagle (Haliaeetus albidlla) in Poland over 6 yr (1997- 2002) . Our work represents the first multi-year observa- tions of mites using raptor nests. Materials and Methods Nest material was collected during visits to occupied nests within the ranges of two pairs of White-tailed Sea- Eagle between 9 May and 2 June 1999-2002. Unlike the nests of passerines, in which the entire nest is collected and analyzed after fledging, we collected only ca. 250- 330 g of the lining material from the nest cup (<0.1% of the entire nest mass). The samples were collected from both nests. One was built in a Scotch pine (Pinus sylvestris) in a forest cluster of about 120 yr of age in the Bytnica forest district (52°00'N, 15°10'E). The nest was 1.5 m high, 1.8 m in diameter and weighed ca. 500 kg. The area around the nest comprised moss and boggy ground on the northwest side and a large pine forest in other directions. Samples from this nest were collected for 6 yr on the following dates: 21 May 1997, 22 May 1998, 6 May 1999, 2 June 2000, 28 May 2001, and 29 May 2002. The nest was oc- cupied in all years by a pair of White-tailed Sea Eagles, and broods fledged successfully with the exception of the year 2000, when eggs were laid hut did not hatch. The second nest was located in Podanin forest district (53°00'N, 16°50'E) and was built in an oak {Quercus^>.) within a beech-dominated forest {Fagus sylvatica). This nest was one of the largest sea eagle nests in western Poland (ca. 2.30 m deep and 2.0 m wide, weighing ca. 700 kg), and was built from mostly beech boughs with some pine and oak branches (Mizera 1999). The cup- hning material was comprised of dry grass that probably had been collected from within the forest. Samples from this nest were collected during 3 yr on the following dates: 9 May 1998, 11 May 1999, and 20 May 2000. In all years, fledglings were produced. The mites were extracted in a Tullgren funnel (Karg 1993) and preserved in 75% ethanol. Prior to identifi- cation the specimens were kept in lactophenol. Mites were identified with Axioscop 2 Zeiss microscope equipped with Nomarsky contrast (Zeiss, Oberkochen, Germany) . The species compositions between the two nests and among the different years were compared. Zoocenologi- cal analysis of the mite community was based on numer- ical species percentage dominance (dominancy = D) and frequency in samples. Dominant species were taken as those with proportions over 10% of the mite community. The most frequently occurred species were divided into two groups; 30-50% and >50%. The S 0 rensen similarity index and the Shannon diversity index (TT) of the mite assemblage were calculated and tested according to Ma- guran (1988). The collected mites were deposited in the Invertebrates Databank (Department of Animal Taxono- my and Ecology, Adam Mickiewicz University, Poznan, Po- land) . Results and Discussion Mite communities recorded in the two nests differed from one another both in generic composition and rel- ative abundance of mite species (Table 1). Those differ- ences were clearly visible in samples from both nests and in the subsequent years of the survey. Even within one nest, there was wide variation in the apparent abundance of mites and the variety of species that were represented between samples. Samples collected from the Bytnica nest included 11 (2001) to 419 (2002) mite specimens, and 5 (2000) to 15 (2002) species. The Podanin nests contained 11 (2000) to 334 (1998) specimens, and 4 (2000) to 10 (1998) species. The total number of species of Mesostigmata mites in the Bytnica nest was 29 (696 specimens) , while the number of species in the Podanin nests was only 15 (364 specimes) . Out of 35 mite species identified, only 9 (25.7%) were found in both nests. The Sprensen similarity index (cal- culated from paired samples collected in 1998-2000) was very low (similarity = 25%), suggesting that the mite communities in these two nests were distinct from one another. Uroseius infirmus was the most common species in the Bytnica nest in 1997 (D = 53%) and 1999 {D = 34%). In 1998 Macrocheles merdarius was most common (78%); in 2000 Androlaelaps casalis was most dominant (74%); while in 2001 there were no dominants; and in 2002 three species were dominant: Parasitus fimetorum (32%), Alliphis siculus (20%), and Macrocheles ancyleus (12%). Alliphis siculus (87%) was dominant in the Podan- in nest in 1998, Nenteria pandioni (53%) in 1999, and in 2000 there were no dominants. Over the 6 yr of survey, the most commonly identified species in the Bytnica nest was Parasitus fimetorum, which was also one of the most common in the Podanin nest (examined for 3 yr) . The second most numerous species in the Bytnica nest was Alliphis siculus, which appeared “super-dominant” in the Podanin nest, comprising 80% of all mites. However, the third and fourth most numerous species in the Bytnica nest (i.e., Uroseius infirmus and Macrocheles merdarius) were totally absent from the Podanin nest (Table 1). Zoocenologic analysis was also based on frequency cal- culations. It appeared that Uroseius infirmus (100%) and Trichouropoda ovalis (83%), classified as euconstants, were the most frequent mites in the Bytnica nest. We classified Alliphis siculus (67%) and Asca nova (67%) as constants. Nenteria pandioni (100%) was the most frequent in the Podanin nest. We noted that only two species of Uropo- dina suborder {Nenteria pandioni, Trichouropoda ovalis), were commonly found in both nests (56—78%) and oc- curred regularly in all years. Apart from the two Uropo- 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 Androlaelaps casalis 7F, 2M 5F, IM 18F, 8M IF Amblyseius sp. Ameroseius corbiculus IF IF, IM Ameroseius elegans Asca nova 3F IF IF Cornigamasus lunaris Dendrolaelaps latior Dendrolaelaps wengrisae Dendrolaelaps sp. IIF, IM IF, IM ID IF, ID Gamasellodes bicolor IF IF Halolaelaps sp. Iphidozercon gibbus Lasioseius sp. 5F, 4D IF ID Leioseius sp. Macrocheles ancyleus Macrocheles glaber Macrocheles merdarius Macrocheles tridentinus 55F, 25M IF Neojordensia sinuata Paragamasus vagabundus IF IF IF Parasitus coleoptratorum Parasitus fimetorum Pergamasus mediocris Proctolaelaps pygmaeus 3F, 2M Prozercon kochi IF Typhlodromus pyri IF Vulgarogamasus kreaepelini Zercon curiosus Zercon triangularis Zercon zelavaiensis ID IF, IM IF, IM, 16D 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 2002 Total Speci- mens Domi- NANCY [%] 1998 1999 2000 Total Speci- mens Domi- nancy (%) 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 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- cies may be influenced by stochastic factors. We suggest that the mite communities in these nests were highly in- stable, and that the generic compositions were the result of random factors. Changes in the number of genera ob- served over the years were clearly correlated with the changes of mite numbers (r = 0.81; P < 0.01). The Shannon diversity index differed between years in both nests (Bytnica nest, H = 1.709 ± 0.816; Podanin nest H = 1.082 ± 0.444) and probably was related upon whether or not the nest was successful, because the lowest species diversity (iT = 0.828) was recorded in the nest with no nestlings. The generic diversity recorded in the nest when no nestling was reared differed significantly {t = 2.42, df = 5, P = 0.05) from that recorded in the same nest in successful years. Variation in the number of mite species and abun- dance during this survey support the hypothesis of high variability of the Mesostigmata community in the unsta- ble microhabitat of White-tailed Sea Eagle nests. Howev- er, our results were based on only two nests. Also, we do not know whether our removing of samples each year may have affected the mite community that was present the following year. Three species of the Uropodina suborder, Nenteria pan- dioni, Uroseius infirmus, and Trichouropoda orbicularis, seemed to be typical nidicoles associated with White- tailed Sea Eagle nests. All three species are phoretically transferred by insects. However, the most consistently-oc- curring species in the microhabitat of the eagle nests among Gamasina were Alliphis siculus, Asca nova, Perga- masus vagabundus, and Parasitus fimetorum. Because eagle nests are reused year after year and mite species can persist from one year to the next, the year to year variety of mites that might be available to populate a nest may be masked. The eagle nest mite populations did not show regular, seasonal changes, but rather chang- es were irregular with no distinct trends. We suggest that eagle nest mite occurrence and abundance depends mainly on changes in climatic conditions throughout the year and the microclimate inside the nest, and is related to nest specific differences (e.g., nest success, nest-lining composition, amount and type of prey remains, and the amount of excrement) . Importantly, the availability of po- tential prey for the mites depends on the presence of decaying flesh (mainly fish and water birds) in the nest, and the amount of eagle excrement. Fluctuation in rap- torial-mite numbers may also be influenced by the oc- currence of nematodes, and the eggs and larvae of some insects upon which the mites feed. Our results on the species structure of mesostigmatic mites recorded in White-tailed Sea Eagle nests were sim- ilar to results on acarofauna found in other raptor nests, including the Spotted Eagle {Aquila clanga) , Lesser Spot- ted Eagle {A. pomarina), Osprey (Pandion haliaetus). Red Kite {Milvus milvus), Black Kite {M. migrans), and Com- mon Buzzard {Buteo buteo) (Gwiazdowicz et al. 1999, 2000, Gwiazdowicz 2003) . However, preliminary compar- isons with White Stork ( Ciconia ciconia) and small passer- ines from nest boxes (Gwiazdowicz 2003, J. Bloszyk un- publ. data) suggest differences from these kinds of nests For example, in White Stork nests Alliphis siculus (a dom- inant species in White-tailed Sea Eagle nests), was not found. In contrast Androlaelaps casalis was detected as a dominant species in nest boxes but was rare and uncom- mon in White-tailed Sea Eagle nests. The results presented here are preliminary and further research is needed, especially to examine potential rela- tionships between mite fluctuations and features of the nest. Acaros (Acari: Mesostigmata) Presentes en Dos Nidos DE HALIAEETUS ALBICILIA Resumen. — Se estudiaron los acaros del suborden Mesos- tigmata en dos nidos de Haliaeetus albicilla. Las muestras del primer nido fueron colectadas a lo largo de seis ahos y las del segundo a lo largo de tres ahos. Los grupos de acaros de los dos nidos presentaron diferencias marcadas en cuanto a composicion generica y abundancia relativa. En el primer nido se registraron 29 especies y 696 espe- cimenes, mientras que en el segundo solo se encontraron 15 especies y 364 espedmenes. En total, en los dos nidos se encontraron 35 especies, de las cuales solo nueve fue- ron abundantes en ambos nidos. Las especies dominan- tes en el primer nido fueron Parasitus fimetorum (19.54%), Alliphis siculus (14.37%) y Uroseius infirmus (12.93%), y en el segundo dominaron Alliphis siculus (79.95%) y Nenteria pandioni (8.79%). [Traduccion del equipo editorial] Acknowledgments A grant by the August Cieszkowski Agricultural Uni- versity of Poznan and Adam Mickiewicz University (Re- search Project No. 5/L/15/WJ/03) funded this work. Thanks also to M.J. McGrady, J. Phillips, and two anony- mous referees who reviewed and improved this manu- script. Literature Cited Gwiazdowicz, DJ- 2003. Mites {Acari, Mesostigmata) ap- pearing in Poland, in the bird’s nests of Passeriformes, Falconiformes and Strigiformes orders. Pages 562-572 tn A.T. Miler [Ed.], Ksztaltowanie i ochrona srodowiska lesnego. Wydawnictwo Akademii Rolniczej, Poznan, Poland. AND T. Mizera. 2002. Preliminary research on mites {Acari, Gamasina) occurring in the pellets of birds of prey and owls. Anim. Sci. J. 4:117-125. , , AND M. Skorupski. 1999. Mites in Greater Spotted Eagle nests./. Raptor Res. 33:257-260. , , AND . 2000. Mites {Acari, Gamasi- na) from the nests of birds of prey in Poland. Buteo 11:97-100. Karg, W. 1993. Acari (Acarina), Milben Parasitiformes March 2005 Short Communications 65 (Anactinochaeta) , Cohors Gamasina Leach. Fischer Verlag, Jena, Germany. KristofikJ., P. Masan, and Z. Sustek. 2001. Mites (Acan), beetles (Coleoptera) , and fleas (Siphonaptera) in the nests of Great Reed Warbler (Acrocephalus arundinac- beus) and Reed Warbler (A. scirpaceus) . Biologia {Bra- tislava) 56:525—536. Maguran, A.E. 1988. Ecological diversity and its measure- ment. Groom Helm, London, U.K. Masan, P. and J. Kristofik. 1995. Mesostigmatid mites (Ac- arina: Mesostigmata) in the nests of Penduline Tit {Re- miz pendulinus) . Biologia {Bratislava) 50:481—485. Mizera, T. 1999. Bielik. Wydawnictwo Lubuskiego Klubu Przyrodnikow, Swiebodzin, Poland. Nordberg, S. 1936. Biologisch-Okologische untersuchun- gen liber die Vogelnidicolen. Acta Zool Fenn. 21:1- 168. Philips, J.R. 1981. Mites {Acarina) from nest of Norwe- gian birds of prey. Fauna Nor. Ser. B. 28:44—47. . 2000. A review and checklist of the parasitic mites {Acarina) of the Falconiformes and Strigiformes. J Raptor Res. 34:210-231. , M. Root, and P. Desimone. 1983. Arthropods from a Saw-whet Owl {Aegolius acadicus) nesting m Connecticut. Entomol. News. 94:60—64. TRYfANOWSKI, R, E. Baraniak, R. Bajaczyk, DJ. Gwiazdow- icz, S. Konwerski, Z. Olszanowski, and P. Szymkowiak. 2001. Arthropods in nests of the Red-backed Shrike {Lanius collurio) in Poland. Belg. J. Zool. 131:69—74. Received 16 February 2004; accepted 25 October 2004 J. Raptor Res. 39(l):65-69 © 2005 The Raptor Research Foundation, Inc. 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- lands; diet, prey biomass; Argentina; Paraguay. In South America, the diet of the Barn Owl ( Tyto alba) has been studied primarily in temperate and arid regions of Argentina and Chile (Jaksic 1996, Pardinas and Cir- ignoli 2002). In the vast tropical and subtropical-humid areas this owl is poorly known (e.g., Motta-Junior 1996, Bellocq 2000, Vargas et al. 2002). Here, we describe the vertebrate prey consumed by Barn Owls in the subtropi- cal wetlands of the Ibera-Neembucu system (Argentina and Paraguay). Study Area The Esteros del Ibera (Corrientes Province, Argentina) IS a Ramsar site of 13 000 km^, making it one of the larg- est wetlands in South America. The Esteros del Neem- bucu (Neembucu Department, Paraguay), with ca. 4000 km^, cover an extensive region on the left bank of Para- guay River. Both wetlands (Fig. lA) display a complex 1 Email: antheca@yahoo.com.ar mosaic of marshes, “embalsados" (massive carpet of float- ing vegetation, mostly composed of accumulated, dead, and decomposing plant material). These wetlands are in- termixed with extensive palms of Copernicia alba and gal- lery forest, and have remained mostly unmodified by hu- man activities (Carnevali 1994). The climate is humid subtropical (according to Koppen’s [1931] classification scheme), with a mean annual temperature of 23-C and mean annual precipitation of nearly 1350 mm (Carnevali 1994). Methods The owl-pellet samples {N = 14) were collected during the breeding seasons of 2001-02 and 2002—03 (Septem- ber-December) from human buildings at 1 1 localities m the Ibera-Neembucu wetlands (Fig. lA). Because of the humid environment, pellets rapidly disintegrated (<1 mo). Therefore, the precise number of pellets included was undetermined. We also included two samples of pel- let debris (localities of Ensenadita and Desaguadero) 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- 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. Mass PlIAR (1) Ensena- DITA (2) Desagua- DERO (3) El Som- brero (4) El Pon- ton (5) Ea. Cerro Pyta (6) Ea. San Ignacio (V) 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- mains were identified by comparison with the reference mammal collection of the Centro Nacional Patagonico, Puerto Madryn, Argentina. We followed the taxonomy in Galliari et al. (1996). For each prey type, we quantified the minimum number of individuals (MNI; determined by skull bones) and the percent biomass contribution to the diet (percent biomass = [100 NJ/2 pi N^, where = mean prey ^ mass and A( ~ number of individuals of the prey i). The mean prey mass were taken from liter- ature (Redford and Eisenberg 1992) and from specimens trapped in Corrientes Province (unpubl. data). Mass of the marsh rat {Holochilus sp.) counted in pellets was es- timated from comparisons to skeletons of this rodent of known mass collected near the study area. Large adult Holochilus may exceed 200 g in body mass; we used a mean mass of 150 g for this species in biomass estima- tions. The trophic niche breadth was measured accord- ing to the Levins index, food-niche breadth (FNB = 1/ 2 p,^, where pi = proportion of each prey), and the standardized Levins index (FNBs = [FNB — minimum] / [FNB maximum — FNB minimum], where FNB mini- mum = 1 and FNB maximum = maximum number of prey categories [species for mammals, classes for am- phibians and birds]; Marti 1987). Results and Discussion We identified 2262 prey items, mostly native-sigmodon- tine rodents (>90%). The more frequently preyed-upon species were the oryzomines Holochilus sp. and Oligoryzo- mys cf. O. flavescens. Other muroids recorded were Akodon March 2005 Short Communications 67 Table 1 . Extended. Paso Lucero (8) Ea. San Antonio (9) Ea. El Estribo (10) Ea. Yaguarete Cora (11) Ea. IberA (12) P.N. Mburu- cuya (13) Pto. Maria 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 Q 0.5 4.0 — 1 — — 1 — — 1 0.3 c 3 14 3.8 12 1.1 — — — — — 1 2 — — — — — 4 1.7 — — — — — — — 4 3 0.2 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- rus rufus, and Scapteromys aquaticus. The Barn Owl also consumed variable numbers of marmosine marsupials, molossid bats, birds, and amphibians (Table 1 ) . Although the representation of the latter groups in pellets was lim- ited, the bat Eumops patagonicus was the most common prey in the Ensenadita sample. On the other hand, the marmosine marsupials were the second most frequently consumed prey in the samples from the estancias Cerro- Pyta and San Ignacio. In terms of biomass, Holochilus sp. was the most im- portant prey in the diet (31.1-87.9%), followed hy Akodon azarae, Cavia aperea, and Scapteromys aquaticus, with esti- mates generally <15% (Table 1). The prey mass range was between 8 g (amphibians) and 445 g {Lutreolina cras- stcaudata). The geometric mean of weight of prey (GMWP) was 34.9-138.6 g. Six samples showed GMWP values >80 g (110.2 ± 21.1 g; x ± SD). For South Amer- ican temperate latitudes, Marti et al. (1993) reported a GMWP of 45.1 g. Clearly, the greater values obtained for the Ibera-Neembucu system were related to a greater consumption of prey with mass >100 g. The high pre- dation on Holochilus sp. (150 g) was unusual, because Barn Owls typically capture smaller prey (Taylor 1994) Similar results were reported by Vargas et al. (2002) in a tropical flooded savanna from northern Bolivia and by Massoia et al. (1997, 1999) for owls inhabiting the right bank of the Rio Parana in the Argentinean provinces of Chaco and Formosa. Most of the Holochilus sp. individuals recovered in Ibera-Neembucu pellets were, on the basis on tooth wear, full adult or old-adult specimens. This im- plied that the actual mass of these individuals was close 68 Short Communications VoL. 39, No. 1 Figure lA, Map of the study area, northeastern Argen- tina and southeastern Paraguay, showing the localities discussed in the text in the Neembucu-Ibera wetlands. IB. Specific richness (rodents) found in pellets of Barn Owls from Ibera-Neembucu wetlands. Only localities with more than 50 individual prey items identified were in- cluded. Locality names for numbers are provided in Ta- ble 1. to 200 g (Massoia 1976). On the other hand, in samples mainly composed of smaller species (e.g., Ahodon azarae, Eumops patagonicus, Oligoryzomys spp.) , the GMWP varied between 34.9-57.4 g, with a mean value (46.9 ± 8.2 g), similar to the value previously reported by Marti et al. (1993). 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 are similar to those previously estimated by Bellocq (2000) for the Ensenadita and Desaguadero samples (FNBs = 0.25 ± 0.04). In South America, Marti et al. (1993) reported a FNB of 4.28 (FNBs = 0.48) in tem- perate latitudes, and 4.61 (FNBs = 0.38) in tropical lati- tudes. The lower values of the Levins index for the Ibera- 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 riv- ers. 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 wet- lands 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 re- flected in the Barn Owl diet (Fig. IB). The species rich- ness 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 mar- ginal localities this value reached 10 {N = 4 samples, x = 8.5 species). These contrasts, comparing central and peripheral lo- calities, 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 con- trast 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 system (Alvarez et al. 2002) . Perhaps, most of the anurans of the Neembucu-Ibera system were “avoided” by owls because of their cryptic habits and small body mass (<8 g) . Antipredator mechanisms in toads and frogs also in- clude defensive postures and toxic or noxious skin secre- tions that may deter predation hy Barn Owls. On the other hand, the high consumption of Holochilus in these 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- eas, and the enormous densities of this marsh rat m subtropical wetlands (Massoia 1976). Vertebrados Presa de Tyto alba en Humedales Sub- TROPICALES DEL NORDESTE DE ARGENTINA Y ESTE DE PAR- AGUAY Resumen. — Se estudio la dieta de Tyto alba en los hume- dales del complejo de esteros Ibera-Neembucu, ubicados en el nordeste de Argentina y este de Paraguay. Se iden- tificaron 2262 presas, con una neta predominancia de roedores sigmodontinos nativos (>90%). Holochilus sp. y Oligoryzomys cf. O. flavescens fueron las especies mejor re- 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- plitud de nicho trofico fluctuo entre 1. 5-4.1. Es desta- cable el importante consumo de presas con un peso >100 g, que se refleja en una media geometrica del peso de las presas >80 g. Igualmente destacables son los bajos valores de riqueza de roedores que se observan en aque- llas localidades centrales al sistema de humedales (entre 2—6 especies), en contraste con los observados en loca- lidades perifericas del oeste (entre 6-11). En estos am- bientes inundables subtropicales, la dieta de T. alba se focaliza basicamente en el consumo de Holochilus sp., un roedor anfibio netamente nocturno que alcanza grandes densidades poblacionales. [Traduccion de los autores] Acknowledgments We thank the many individuals that freely provided samples, data, or field and laboratory assistance for this study: A. Andrade, J.R. Contreras, Y Davies, S. Fabri, L.M. Fuschetto, M. Merino, and A. Soria. We appreciated the improvements in English usage made by Stacy Small through the Association of Field Ornithologists’ program of editorial assistance. Field work was supported by Ibera Project (Universidad Nacional del Nordeste, Corrientes). This work was partially funded by the Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) . Literature Cited Alvarez, B.B., R.H Aguirre, J.A. Cespedes, A.B. Hernan- do, AND M.E. Tedesco. 2002. Atlas de anfibios y rep- tiles de las provincias de Corrientes, Chaco y Formo- sa, Argentina: anuros, cecilidos, saurios, anfisbenidos y serpientes. Univ. Nacional del Nordeste, Corrientes, Argentina. Bellocq, M.I. 2000. A review of the trophic ecology of the Barn Owl in jArgentina. y. Raptor Res. 34:108-119. Carnevali, R. 1994. Fitogreografia de la Provincia de Corrientes. Institute Nacional de Tecnologia Agro- pecuaria, Edicion de la Gobernacion de la provincia de Corrientes, Corrientes, Argentina. Fabri, S., S. Heinonen Fortabat, A. Soria, and U.F.J. Pardinas. 2003. Los mamiferos de la Reserva Provin- cial Ibera, provincia de Corrientes, Argentina. Pages 305-342 in B.B. Alvarez [Ed.], Fauna del Ibera. Edi- torial Universitaria de la Universidad Nacional del Nordeste, Corrientes, Argentina. Galliari, C.A., U.F.J. Pardinas, and F. Goin. 1996. Lista comentada de los mamiferos argentinos. Mastozool. Neotrop. 3:39—62. Jaksic, F. 1996. Ecologia de los vertebrados de Chile. Ed- iciones de la Universidad Catolica de Chile, Santiago, Chile. Koppen, W. 1931. Grundiss der Klimakunde. Walter de Gruyter Co., Berlin and Leipzig, Germany. Marti, C.D. 1987. Raptor food habits studies. Pages 67- 80 in B. Giron Pendleton, B.A. Millsap, K.W. Cline, and D.M. Bird [Eds.], Raptor management tech- niques manual. National Wildlife Federation, Wash- ington, DC U.S.A. , E. Korpimaki, and F. Jaksic. 1993. Trophic ecol- ogy of raptor communities: a three-continent com- parison and synthesis. Curr. Ornithol. 10:47-137. Massoia, E. 1976. Mammalia. Pages 1-128 mR. Ringuelet [Ed.], Fauna de agua dulce de la Republica Argenti- na. Fundacion Editorial Ciencia y Cultura, Buenos Ai- res, Argentina. , J.C. Chebez, and S. Heinonen Fortabat. 1988. Presas de Tyto alba tuidara en Ensenadita, departa- mento San Cosme, provincia de Corrientes. Biol, dent. Natur. 12:8-14. , , AND . 1990. Mamiferos depreda- dos por Tyto alba tuidara en Desaguadero, departa- mento capital, provincia de Corrientes. Biol. dent. Na- tur. N^ 18:14-17. , S. Heinonen Fortabat, and A.J. Dieguez. 1997 Analisis de componentes mastozoologicos y ornitolo- gicos en regurgitados de Tyto alba de Estancia Guay- colec, departamento. Pilcomayo, provincia de For- mosa, Republica Argentina. Biol. dent. Natur. N- 32 12-16. , H. Pastore, and S. Heinonen Fortabat. 1999 Analisis de regurgitados de Tyto alba en escuela pro- vincial N-17 “J. Sabiaur” departamento Bermejo, provincia de Chaco. Biol. dent. Natur. N- 36:2-4. Motta-Junior, C.J. 1996. Ecologia alimentar de corujas (Aves, Strigiformes) na regiao central do estado de Sao Paulo: biomassa, sazonalidade e seletividade de suas presas. Tese de Doutorado, Univ. Federal de Sao Carlos, Sao Carlos, Brazil. Pardinas, U.F.J. and S. Cirignoli. 2002. Bibliografia com- entada sobre los analisis de egagropilas de aves rapa- ces en Argentina. Ornitol. Neotrop. 13:31-59. Redeord, K.H. andJ.F. Eisenberg. 1992. Mammals of the neotropics. Vol. 2. The southern cone: Chile, Argen- tina, Uruguay, Paraguay. Univ. Chicago Press, Chica- go, IL U.S.A. Taylor, I. 1994. Barn Owls, predator-prey relationships, and conservation. Cambridge Univ. Press, Cambridge, U.K. Vargas J., C.A. Landaeta, and J.A. Simonetti. 2002. Bats as prey of Barn Owls ( Tyto alba) in a tropical savannah in Bolivia./. Raptor Res. 36:146-148. Received 20 November 2003; accepted 26 November 2004 J Raptor Res. 39(l):70-74 © 2005 The Raptor Research Foundation, Inc. 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, Morocco; wintering. The Eurasian Griffon {Gyps fulvus) is a Palearctic spe- cies distributed from North Africa, south and southeast- ern Europe to the Middle East into southwestern and central Asia (Cramp and Simmons, 1980, del Hoyo et al. 1994). In the last three decades the Spanish population has greatly increased (SEO BirdLife 1981, Arroyo et al. 1990, del Moral and Marti 2001). Migration of the spe- cies into Africa through the Strait of Gibraltar to Moroc- co and countries south of Sahara has been studied for a long time (Elosegui and Elosegui 1977, Bernis 1983, Aonso 1984, Griesinger 1998). However, there is limited recent information on the status of the species in Mo- rocco. The information available only describes breeding colonies documented in the past (Soto 1986, Bergier 1987). Mundy et al. (1992) referred to some colonies in the Rif Mountains close to Tangier and additional ones from Figuig in the east to Goulimine on the west of the Anti-Atlas, with no breeding places in the Sahara Moun- tains. According to Haddane (1996) and others, the dis- tribution of griffons in Morocco has been reduced dras- tically by human activities, and generally recent information (Mundy 2000, Thevenot et al. 2003) was not supported with fieldwork. The extent of the population decline of griffons and their winter distribution in Mo- rocco remain unknown. Our aim here is to: (1) survey for the Eurasian Griffon breeding colonies in northern Morocco and (2) analyze the recoveries of ringed birds from Spain to identify potential wintering grounds. The status of the species in Morocco is relevant to its conser- vation. Al migrating western European vultures cross ^ Email address: acamia@vodafone.es through this country before reaching wintering grounds in the southern Sahara. Study Area and Methods This study was done in northern Morocco, from the North Atlantic Coast (60 km north of Kenitra) to the eastern Sahara Desert (Plateau du Rekkam) through the Rif (Ouazzane-Chefchauoen-Ketama-Midar to Oujda) and the Middle Atlas Mountains (from Meknes to Taza) , and from Guercif into An-Benimathar south as far as Bouarfa, near Figuig. The southernmost surveyed point in central Morocco was Meknes. The study area is similar to the Spanish side of the Strait of Gibraltar from the ecological and geological points of view (Valdes 1991) Many large limestone mountains provide cliffs with suit- able caves and surfaces for Eurasian Griffons to breed (del Hoyo et al. 1994). On the Spanish side, one of the largest breeding subpopulations in Spain was found (del Junco and Barcell 1997, del Moral and Marti 2001). How- ever, on the Moroccan side there were breeding colonies only in the past (Soto 1986, Bergier 1987, Thevenot et al. 2003). Some authors believe that griffons may still breed there in Morocco, but the whole area has been heavily populated and hence changed dramatically (Had- dane 1996). Roadside counts covering ca. 2800 km were done dur- ing one entire month (1-28 February 2002). On those dates, adult Eurasian Griffons are breeding (laying or in- cubating) and non-adult migrating birds should still be on their wintering grounds (del Hoyo et al. 1994, pers obs.). Our survey was done using a vehicle, at a speed of ca. 40-50 km/h with stops when colonies were located We looked for cliffs with raptor excrement (white wash), as well as perched and flying vultures (Fuller and Mosher 1981, Donazar et al. 1993). We searched for griffons at any suitable cliff within view of our road surveys and at 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 assumed that our detection probability of the birds from 70 March 2005 Short Communications 71 the road survey routes was very high. Detection of grif- fons 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 in- dividuals to help determine if they had seen these vul- tures. 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 status in Morocco we examined all the recoveries of birds ringed in Spain from 1965-2002. The following databases were reviewed: Centro de Migracion de Aves (SEO/ BirdLife) , Direccion General de Conservacion de la Na- turaleza (DGCN) from the Spanish Ministry of Environ- ment, and Museo de Ciencias Aranzadi from San Sebastian. Results We did not see any griffons during the roadside census or breeding at any previously-reported colonies. We searched for colonies, but found none in the Jebel Mous- sa in Tangier region, the Jebel Bouhachen Nature Re- serve, and Jebel Haouz (Soto 1986). We surveyed Bab Taza, visiting Tissouka, Lahkrtia, Jebel el-Kelaa, Jebel Ab- doune, and Talambote, as well as the Oued Laou can- yons. We also passed through Talaseemtane National Park and the Ketama (Jebel Tidiquim) Mountains sur- rounding de Targuist and Al-Hoceima National Park, close to the coast. In addition, we visited the Middle Atlas at Tazzeka National Park. Other colonies mentioned by Soto (1986) and visited with negative results were Bou Bgar (Gorges de la Moulouya), nearby Oujda city. Fur- thermore, two recorded colonies in Massif des Beni Snas- sen had no griffons. Our lack of detections suggests that there were neither breeding nor wandering birds in the study area. During our roadside counts we easily detected several cliff-nesting raptors such as Bonelli's Eagles {Hi- eraaetus fasdatus), Peregrine Falcons {Falco peregrinus), and Golden Eagles {Aquila chrysaetos), all more difficult to detect than Eurasian Griffons. Therefore, we believe that we did not overlook the latter species. Two rubbish dumps were visited, one south of Tangier and another close to Chefchaouen to the east. None of these seemed to support griffons, although there were large numbers of White Storks ( Ciconia dconia) . Our previous visits to Morocco had revealed no griffons in the L'Oum or Rbia and El Menzel colonies in 1986 and 1994, respectively. Of 55 questionnaires, only 50 were judged to provide valid information. Based on their reports, 26 respondents observed Eurasian Griffons in the last decade, 24 within Figure 1. Map of Morocco showing the recoveries of Griffon Vultures ringed in Spain (numbers as in Table 1) and locations of reported observations of griffons 1^1 The study area in northern Morocco is outlined. the study area, plus one in the eastern desert and anoth- er in the Atlas Mountains (Fig. 1). All were made on the Mediterranean side of Morocco and in the Rif Moun- tains. People interviewed said that groups of vultures were never seen for long periods. The mean group size was 6.5 ± 6.2 (SD) griffons (range = 1—73). Further- more, no information was reported on recent breeding colonies. Only one record involved griffons feeding on a carcass near Tangier. Observations were sparsely distrib- uted throughout the year: five in winter (December-Feb- ruary), seven in spring (March-May), four in summer (June-August), and three in autumn (September-No- vember). Observers provided six records (20.8%) for which they could not recall the season. Everyone inter- viewed pointed out that griffons, as well as other raptors, were shot and even consumed by man. Moreover, five older residents remembered the species from their youth, when wild ungulates and big felids, such as lions {Panthera led) or leopards {Panthera pardus) , inhabited the area. These individuals reported that griffons were pres- ent in the 1960s and 1970s. Finally, one observer report- ed six griffons in the Middle Atlas Mountains (near Azrou) , although he was unable to recall the date and if they were migrant or resident. Bedouin shepherds indi- cated that every winter a small griffon population re- mains in the desert located in the Eastern Atlas Moun- tains, where there is a winter food supply from sheep carcasses. We found only nine recoveries of Spanish ringed grif- fons in different locations of Morocco (Fig. 1 and Table 1). Most of them (except recoveries 8 and 9) were ringed as nestlings, but all were probably ringed as juvenile birds. Where information was available, most of the deaths were attributed to malnutrition (Table 1). Three had died recently, two were sighted alive, and a sixth grif- 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 Num- ber Age of Ringing Date of Ringing Coordi- nates of Ringing Province of Ringing Circumstances OF Recovery Date of Recovery Coordi- nates OF Recovery Location of Recovery 1 Nestling 25 Jun 67 42.55N 01.51W Navarra Captured 02 Nov 70 33.47N 06.02W Souk KLhemis Ait Yadine 2 Nestling 19 May 7l 42.38N 00.49W Huesca na 01 Dec 72 33.16N 05.05W Timandite 3 Nestling 12 May 79 40.56N 00.15W Teruel Corpse alone found 02 Oct 80 30.29N 08.52W Taroudant 4 Nestling 29 May 84 36.35N 05.50W Cadiz na 29 Nov 84 33.50N 06.03W Khemisset 5 Nestling 11 May 85 41.21N 03.50W Segovia Malnutrition 06 Jun 86 33.15N 08.40W Jorf Lasfar 6 Nestling 10 May 86 41.29N 09.40W Soria Predated 06 Jul 87 30.30N 09.40W Toulgharb 7 Nestling 18 May 96 42.50N 03.06W Alava na 24 Feb 98 35.53N 05.19W Ceuta 8 na 27 Nov 98 37.00N 06.30W Huelva na 07 Jan 99 32.16N 04.30W Rich 9 Fledgling 10 Sep 99 41.34N 03.41W Burgos Malnutrition 19 Nov 99 34.57N 03.33W Midar nine griffons were ringed in different Spanish provinces. Finally, three were ringed in the 1960s or 1970s, four in the 1980s, and four in the 1990s, with no increases in recoveries despite the increases of both the Spanish pop- ulation and the number of griffons ringed (del Moral and Marti 2001, Gomez-Manzaneque et al. 2002). Discussion Our survey revealed a complete lack of breeding or wintering Eurasian Griffons in northern Morocco. This could reflect the alarming decline of the species reported by Soto (1986) and Thevenot et al. (2003). According to these authors and this current study, the Eurasian Griffon could be extirpated as a breeding species in this region and probably in all of Morocco. Reasons for this decline would be lack of food and direct human persecution by means of poaching and poisoning (Soto 1986, Haddane 1996, Thevenot et al. 2003). The same reasons could ex- plain why there are no vagrant griffons in the area, de- spite that the physical habitat appears suitable. Results of inquiries indicated that only migrating griffons from Eu- rope passed over northern Morocco, and that no locally- breeding birds were present. Increasing numbers of grif- fons have been recorded crossing into Africa in recent years with 1633, 2649, and 4816 birds in 1998, 1999, and 2000, respectively (SEO/BirdLife 2001). Furthermore, up to 1524 were recorded at Koudia el Baida (20 km north to Tetouan and 30 km east from Tangier), with 1426 birds counted on 23 October during a survey in 2001 (R Bergier pers. comm.). To date, the migration period and pattern of griffons has not been analyzed in detail (Bernis 1983, Franchimont and Moumni 1996, Griesinger 1998). Migration phenology in the Strait of Gibraltar area extends even later than October, with large numbers still passing in November (SEO/BirdLife 2001). Ring recoveries of griffons were scarce and were not adequate to draw any conclusions. Recent studies with Egyptian Vultures {Neophron percnopterus) tracked with sat- ellite transmitters (Benitez et al. 2003, M. de la Riva pers. comm.) showed broad-band migration over Morocco and that the birds followed a straight flight path southwards over the country and the Sahara Desert. Limited data for griffons seem to show a similar migration pattern, al- though it has been suggested that these vultures follow specific routes as they do in Spain (Garrido et al. 2001). Recoveries of griffons on the Atlantic side could suggest a second coastal route or vagrant birds. Migration along this route would likely take griffons to sub-Saharan win- tering quarters in Mauritania, Senegal, and Mali (del Hoyo et al. 1994, Layna 1999). A small griffon population could remain in the northern Sahara, if food is available. In addition to Spanish recoveries, there is another from a juvenile griffon ringed in the Pyrenees of France as a nestling in early June 1993 and recovered near Meknes within the same year (5 October; Arthur and Peyrusque 2000) that supports the idea of a central broad-band mi- gration of griffons. The percentage of ring recoveries 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- mez-Manzaneque et al. 2002). Probabilities of reporting a ringed bird could be biased relatively high in heavily populated areas, giving a misleading impression of the migration route. Nevertheless, the final destination of griffons should be determined by future studies using satellite transmitters (Camina, 2004). From the conservation point of view, our study indi- cates that the Eurasian Griffon is seriously endangered, if not extinct as a breeding species in Morocco. The de- cline in the griffon population was probably due to a lack of available food and human persecution. For this rea- son, we suggest that it is urgent to examine the status of the griffons in Morocco and other African countries south to the Sahara to provide information necessary to implement conservation measures. Ausencia de Gypsfulvus del Norte de Marruecos Resumen. — Mediante transectos por carretera en el norte de Marruecos (2800 km) y visitas a antiguas colonias de cria, se han buscado evidencias de cria o invernada del buitre Gyps fulvus. Ademas, se han realizado 55 encuestas a habitantes de Marruecos sobre el estatus de la especie. No se ha encontrado ningun buitre criando a pesar del aparente habitat disponible. Los habitantes de la zona indicaron su presencia en el pasado. La persecucion hu- mana puede ser la causa de esta disminucion. Al menos en el area de estudio la especie esta extinta como nidi- ficante. Las recuperaciones de aves anilladas son escasas y se concentran en tres zonas: el desierto del este, las montanas centrales y la Costa Atlantica de Marruecos. Son necesarias urgentes investigaciones sobre el estado del buitre G. fulvus en todo el pais. [Traduccion de los autores] Acknowledgments The travel was financed by Centro de Estudios Super- iores, Marcelo Spinola University of Wales from Umbrete (Sevilla) . Adolfo Rodriguez, Juan Jose Ramos Encalado, Angel Gomez-Manzaneque, and Patrick Bergier provided us with useful observations. Colin Pennycuick and Eiona Grant from Free Spirit Films (Bristol) greatly improved the English text. Peter Mundy and the editor provided helpful comments on an earlier draft of the manuscript. Literature Cited Alonso, J.C. 1984. Sur les quartiers d’hiver des vautors fauves migrateurs. Alauda 52:308-309. Arroyo, B., E. Ferreiro, and V. Garza. 1990. Segundo censo nacional de buitre leonado {Gyps fulvus)'. pob- lacion, distribucion, demografia y conservacion. Co- leccion Tecnica, Instituto Nacional para la Conserva- cion de la Naturaleza, Madrid, Spain. Arthur, C.P. and D. Peyrusque. 2000. Compte-rendu de I'operation 1999 de marquage de vautours fauves dans la reserve nature lie d'Ossau. Rapport PNP/ Ser- vice scientifique N- 99/08/ GR, Parc National des Pyr- enees, Ossau, France. Benitez, J.R., J.A. Sanchez Zapata, J.A. Donazar, M. de la Riva, F. Hernandez, and M. Barcell. 2003. Andalucia se queda sin Alimoches. Quercus 206:15-19. Bergier, P. 1987. Les rapaces diurnes du Maroc. Status, repartition et ecologie. Centre d'Etudes sur les Eco- systemes de Provence, Aix en Provence, France. Bernis, F. 1983. Migration of the common griffon vulture in the western Palearctic. Pages 185-196 in S.R. Wil- bur and J. A. Jackson [Eds.], Vulture biology and man- agement. Univ. California Press, Berkeley, CA U.S.A Camina, A. 2004. Griffon vulture Gyps fulvus monitoring in Spain: current research and conservation projects. Pages 45-66 in R.D. Chancellor and B.-U. Meyburg [Eds.], Raptors worldwide. World Working Group on Birds of Prey and Owls and BirdLife Hungary, Buda- pest, Hungary. Cramp, S. and K.E,L, Simmons (Eds.). 1980. The birds of the western Palearctic. Vol. 2. Oxford Univ. Press, Ox- ford, U.K. DEL Hoyo, J., a. Elliott, and J. Sargatal. 1994. Hand- book of the birds of the world. Vol. 2. Lynx Edicions, Barcelona, Spain. DEL JUNCO, O. AND M. Barcell. 1997. El buitre leonado ( Gypsfulvus) en Cadiz. Junta de Andalucia, Consejeria de Medio Ambiente, Cadiz, Spain. DEL Moral, J.C. and R. Mart! (Eds.). 2001. El buitre leonado en la Peninsula Iberica. SEO/BirdLife, Ma- drid, Spain. Donazar, J.A. 1993. Los buitres ibericos: biologia y con- servacion. J.M. Reyero Ediciones, Madrid, Spain. , O. Cebaixos, a. Travaini, and E. Hiraldo. 1993. Roadside raptor surveys in the Argentinean Patagon- ia. /. Raptor Res. 27:106-110. Elosegui, J. and R. Elosegui. 1977. Desplazamientos de buitres comunes {Gyps fulvus) pirenaicos. Munibe 29 97-104. Franchimont, j. and T. Moumni. 1996. Suivi partiel de la migration post-nuptiale des rapaces diurnes sur la rive du sud du detroit de Gibraltar en 1995. Porphyno 8:55-76. Fuller, M.R. and J.A. Mosher. 1981. Methods of detect- ing and counting raptors: a review. Stud. Avian Biol. 6' 235-246. Garrido, J.R., A. Camina, M. Surroca, and J. Mottos. 2001. Migration of the Eurasian Griffon Vulture {Gyps fulvus) through the Iberian Peninsula. Raptor Re- search Foundation and Estacion Biologica de Don- ana, Sevilla, Spain. Gomez-Manzaneque, A., F. Hernandez-Carrasquilla, O. Corral, and R. Moreno-opo. 2002. Informe sobre la campana de anillamiento de aves en Espana. Ecologia 16:343-376. Griesinger, j. 1998. Juvenile migration and dispersion among griffon vultures Gyps fulvus in Spain. Pages 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 an international conference. World Working Group on Birds of Prey and Owls, Badajoz, Spain. Haddane, B. 1996. The impact of human activities and rehabilitation of raptors: case study, current situation of raptors in Morocco. International Conference on Raptors 1996, The Raptor Research Foundation and the University of Urbino, Urbino. Italy. Lavna, F.J. 1999. Eurasian Griffons Gyps migrating into Cap Blanc, Mauritania, Western Sahara. Vulture News 36:35-36. Mundy, P. 2000. The status of vultures in Africa during the 1990s. Pages 151-164 in R.D. Chancellor and B.- U. Meyburg [Eds.], Raptors at risk. World Working 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. SociEDAD Espanola de Ornitologia/BirdLife. 1981 Primer censo nacional de buitreras. Ardeola 26-27' 165-312. . 2001. Seguimiento de la migracion en el estre- cho, ano 2000. Consejeria de Medio Ambiente Junta de Andalucia y Sociedad Espanola de Ornitologia, Madrid, Spain. Soto, P. 1986. Le statut du vautour fauve Gyps fulvus au maroc. Birds Prey Bull. 3:173-181. Thevenot, M., J.D.R. Vernon, and P. Bergier. 2003. The birds of Morocco. British Ornithologists' Union, Lon- don, U.K. Valdes, B. 1991. Andalucia and the rif, floristic links and common flora. Bot. Chron. 10:117-124. Received 3 July 2003; accepted 8 December 2004 J Raptor Res. 39(1): 74—79 © 2005 The Raptor Research Foundation, Inc. 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- ing structures; breeding chronology; reproductive success; pro- ductivity; Arkansas. Raptor numbers and productivity in some regions are clearly limited by availability of nest sites (Newton 1979). A shortage of nest sites may hold raptor populations at a breeding density below the level that food would other- wise support (Newton 1979). There are two types of evi- dence in the literature that support this hypothesis: (1) breeding pairs are scarce in areas where nest sites are absent (but which seem otherwise suitable), and (2) the provision of artificial nest sites is often followed by an increase in breeding density (Newton 1979). Studies done on Barn Owls {Tyto alba) in northern Utah by Marti et al. (1979) supports Newton’s (1979) proposal concerning the effect of limited nest sites. Marti et al. (1979) suggested that prior to the appearance of buildings, a breeding population of Barn Owls was vir- tually nonexistent on his study area due to a paucity of suitable nest sites, but that foraging habitat and prey were ^ The editorial processing and review of this paper were handled by Clint W. Boal. ^ Email address: pratincola@hotmail.com abundant. At this site, Marti et al. (1979) surveyed ca. 50 silos that were used as roosts by Barn Owls, but only one provided a suitable nest site. In 1977, these workers placed nest boxes in 30 silos before the spring nesting period. By the end of 1978, 24 (80%) of the boxes were used by breeding owls (Marti et al. 1979). Similarly, on oil palm {Elaeis guineensis) plantations in Malaysia, Duck- ett (1991) reported that breeding population densities of the Barn Owl {T. a. javanica) were limited by available nest sites, despite high densities of several species of rat {Rattus spp.; ca. 250-400/ha) . Twenty months after Duck- ett (1991) erected 200 nest boxes in a 1000 ha mature palm plantation (1 box/5 ha), 95% were occupied by nesting Barn Owls. As a result, rat damage to palm trees on the plantation had dropped by 18.1% from the be- ginning of the study (Duckett 1991). The studies con- ducted by Marti et al. (1979) and Duckett (1991) support the hypothesis that Barn Owl populations can be limited by the availability of nest sites. Bloom and Hawks (1983) recorded similar results by testing nest-site limitation in American Kestrels {Falco sparverius) in northern California. Of a total of 208 nest boxes examined between 1977-80, 31% were occupied by breeding kestrels (Bloom and Hawks 1983). Bloom and Hawks (1983) suggested that with more strategic March 2005 Short Communications 75 '-T»T» r 7 . D 1.1 j d D'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 reached 50%. Hamerstrom et al. (1973) reported similar results during a 5-yr study of nest box use by kestrels in Wisconsin. We tested the hypothesis of nest-site limitation on a population of Barn Owls in northeastern Arkansas by providing artificial nesting structures. To examine the ef- fect that an increase in potential nest sites had upon the local population, we conducted our research on replicate experimental and control plots. Although there is a wealth of data on reproductive success of Barn Owls in other regions (e.g., Marti 1992, Taylor 1994), there are no data for the species in Arkansas. Thus, another objec- tive of this study was to provide data on the reproductive success of Barn Owls in Arkansas and compare these re- sults with data from other areas. Methods Study Area. Our research was primarily conducted in a 1700-km^ study area in Craighead and Poinsett coun- ties, northeastern Arkansas (35‘’30'-36°N, 90°20'-91°W; Fig. 1). These two counties were bisected north to south by a narrow zone of topographic relief known as Crow- ley’s Ridge. To the west of this ridge, the agricultural landscape of both counties was dominated by rice, soy- bean, and winter wheat. To the east of the ridge, these crops were mixed with cotton. Within the study area we delineated eight study plots (10 X 10 km) with similar cover types. The proportion of agricultural cover in our study plots varied between 89.6-96.8% (x = 93.0%; based on ArcView Geographic Information System [Environmental Systems Research Institute, Inc., Redlands, GA U.S.A.] analysis of USGS dig- ital orthophoto quadrangles [DOQs]). Four of these were east and four were west of Crowley’s Ridge (Fig. 1). The plots to the east of the ridge were covered primarily by a relatively even mix of rice and cotton, with some winter wheat and soybean, while the plots to the west of the ridge were dominated by rice with a small contingent of winter wheat and soybean. We designated two plots on either side of the ridge as “manipulated” areas (i.e.. Figure 2. Details and dimensions (cm) of Barn Owl ar- tificial nesting structures placed in manipulated study plots, northeastern Arkansas, 2000. those in which we placed nest boxes) by the toss of a coin and the remaining served as controls (Fig. 1 ) . Artificial Nesting Structures. In winter 2000, upon re- ceiving permission from landowners, we erected 12 nest- ing boxes in each of the four manipulated study plots (Fig. 1). We placed six nest boxes on man-made struc- tures (i.e., grain bins, machine sheds, abandoned cotton gins) , where there appeared to be relatively low levels of human activity. We secured the other six structures to isolated trees (i.e., natural structures) standing alone or in small aggregations (Bunn et al. 1982) in or along ag- ricultural fields. All nesting structures were placed be- 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 2.4-6.3 m). We began placing nest boxes on buildings and trees on 27 January 2000 and erected the last one on 7 March 2000. As data on Barn Owl nesting chronol- ogy were lacking for Arkansas, we based the timing of our placement of nest boxes on nesting chronology re- ported from other studies (e.g., Marti 1994). Boxes were placed no closer than 1000 m apart. Duckett (1991) sug- gested this spacing (>1000 m) to be adequate for nesting Barn Owls in most locations in Malaysia, as this species is generally not territorial over its hunting areas. Artificial nest structures (design suggested by K. Rowe, Arkansas Game and Fish Commission, pers. comm.) were constructed from 91.4 cm lengths of thick-wall (0.7 cm) polyvinyl-chloride (PVC) pipe, with an inside diameter of 38.9 cm (Fig. 2). At the ends, we secured 1.3 cm thick plywood pieces, coated on both sides with Thompson’s Water Seal (Memphis, TN U.SA.), and inset 2.5 cm from the ends of the pipe. The plywood ends were secured with 3.2 cm length drywall screws (four at each end), and the seam between the plywood ends and PVC pipe was sealed with black silicon caulking. To facilitate drainage, we drilled three 1.3 cm holes in the bottom of the front half of each nest box (Fig. 2) . 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 control plots by day for signs of nesting owls. Likewise, to determine occupancy of artificial nesting structures, we checked all plots in March and June 2000, and again m January, March, June, and September of 2001 (Loo- man et al. 1996). With permission from landowners, we visually inspect- ed all farm structures and abandoned cotton gins in all plots for nests. When nests were found, we recorded the location, clutch size, and number of nestlings for each. Nests were monitored periodically until young reached fledging age (ca. 60 d after hatching; Marti 1992; data presented below). We conducted extensive auditory surveys of all manip- ulated and control plots between 26 April-4 June 2000, and again between 24 May-13 June 2001. We conducted surveys at night from roads within the study plots. Roads were well distributed, primarily at 1.6 km intervals along section lines throughout all plots. We stopped at all hu- man-developed structures suitable for owl use (barns, cot- ton gins, etc.) and woodlots with snags, and listened for 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 (Saul Mineroff Electronics, Elmont, NY U.S.A.; Colvin 1984). With this equipment, begging and contact calls could typically be detected from a distance of ca. 0.5 km. All roads in each of the eight study areas were systemat- ically searched. For the reproductive success study, we also monitored nests located off plots. These were either brought to our attention by landowners, or were found when searching appropriate looking sites such as old grain elevators, cotton gins, and wooden barns. We used the Mayfield Method (1975) to estimate re- productive success. Because of other research objectives, frequency of nest visits were periodic and varied between 2-30 d intervals (typically 10-20 d intervals). For this analysis, we assumed an incubation period of 30.8 d, with 2 3d between egg-laying (Marti 1992). As we could rea- sonably estimate a mean brood-rearing period (v = 59.7; range = 52-67 d) for 10 nests that fledged young in our study area, we used 60 d as the brood-rearing interval for all nests included in the Mayfield analysis. We did not include nests that were found after they failed (e.g., with abandoned eggs) in this analysis. Results Nest Boxes. Of the 48 nest boxes erected, four (8.3%) were occupied by owls before the end of the study (a period of ca. 19 mo) . All four of these nesting boxes had been erected on man-made structures (i.e., pole or ma- chine sheds). On 23 June 2000, a roosting Barn Owl was flushed from a box placed on a machine shed in the Lepanto study plot (Fig. 1). In January 2001, this .same box was found to be occupied by a nesting owl that was incubating eggs and later produced two young. In March 2001, three other nest boxes on the Lepanto study plot were occupied by breeding owls, all of which failed be- fore any young fledged. No nest boxes erected on trees were occupied by Barn Owls during our study. Nesting. We found a total of 27 nests on and off our Table 1. Number of Barn Owl nests located in separate study plots (each 100 km^) in northeastern Arkansas in 2000 and 2001. Study Plot Status'* Number of Nests IN 2000 Number of Nests IN 2001 Bay Control 1 2 Cash Control 0 0 Egypt Control 0 0 Goobertown Control 0 0 Lepanto Manipulated 2 6 McCormick Manipulated 2 2 Otwell Manipulated 1 1 Waldenburg Manipulated 0 0 ®We errected 12 artificial nest structures in each manipulated plot between January and March 2000. No artificial structures were placed in control plots. study plots (Fig. 1), In 2000, 11 Barn Owl nests were discovered. In the 2001 season, eight of the 2000 nest sites were again in use and eight new nest sites were lo- cated. Seventeen of the 27 nests were in four of the eight study plots (Table 1). These nests included four in our nest boxes, nine located by nest searches and checking historical sites, and four in wooden nest boxes erected by landowners prior to our study. Of the nests found in the four study plots, three were located in control plots (x = 0.75) and 14 were in ma- nipulated plots (x = 3.5; Table 1). In 2000, one nest was found in a control plot (Bay) and five were located in three manipulated plots (Lepanto, McCormick, and Otwell). In 2001 we found two nests in the same control plot and nine in the same three manipulated plots (Table 1 ). Ten other nests were found off study plots (Fig. 1), four of which were reported to us by landowners (Radley 2002). Two nest sites were located at the Craighead County Fairgrounds in the city of Jonesboro, and the re- mainder were in agricultural areas adjacent to estab- lished plots. Eight of these nests were at sites occupied by nesting owls in both 2000 and 2001; four nests were located in two wooden nest boxes, two nests were in a tree cavity in successive years, and two were found in an old grain elevator located south of the Otwell plot (Fig. 1 ) . Of the last two nests, one was located on a roof truss of an open shed, and one was in the hay loft of a horse barn. No previously unrecorded nests were located in any plot by the auditory surveys. Breeding Chronology and Reproductive Success. Al- though Barn Owls may produce more than one brood per year (Lenton 1984, Marti 1994), we detected no sec- ond broods during our study. To determine the onset of egg laying, we backdated from the date of fledging for 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 laying for Barn Owls in our study area was 15 February (median = 14 February; range = 9 January-22 March). The earliest date that eggs were actually observed in nests was 8 February and the latest was 5 April. The length of the nesting season (defined here as the period from the onset of first egg laying to fledging of the last young) for the Barn Owl population in our study area averaged 5.8 mo over the 2 study years. Of the 11 Barn Owl nests found in 2000, six success- fully fledged young (55%), two failed, and the fates of three were undetermined. Mean clutch size was 4.5 eggs (range = 3-6, N = 8) and mean number of young fledged per successful nest was 3.0 (range = 1-4, N = 6). Fledging dates ranged from 6 April-10 July {x = 12 May, median = 23 May). In 2001, we found 16 nests, eight of which were at sites that had been used in the previous season. Of the oc- cupied nests, seven fledged young (47%), eight failed, and the fate of one could not be determined. Mean clutch size was 3.1 (range = 1-5, N = 9) and mean num- ber of young fledged per successful nest was 2.6 (range = 1-4, N = 7). Fledging dates of the eight successful nests ranged from 18 May-5 July (x = 6 June, median = 11 June). Mean clutch size for the 2 yr was 3.8 (N = 17) and mean number of young fledged per successful nest was 2.8 (N = 13). Our Mayfield (1975) estimate of Barn Owl nesting success (defined here as the probability of survival of a nest from the start of incubation to the fledg- ing of young) was 0.56 for 23 Barn Owl nests. Discussion Artificial Nesting Structures. The lack of use of our nest boxes in 2000 (no nesting, but one owl documented as roosting) was probably because most were not erected until after many breeding Barn Owls had already selected nesting locations. Owls in our study area typically initi- ated nesting in mid-February. However, most of our nest- ing structures were not in place until mid to late Febru- ary. When we initiated this study, there were no data available pertaining to nesting chronology of Barn Owls m Arkansas and we attempted to erect boxes before an- ticipated nesting in March and April. Because owls start- ed breeding earlier than the original estimated dates for nesting, they may not have had adequate time to find and to habituate to the structures for nesting in 2000. In 2001, all four nest boxes used by breeding owls were located on man-made structures (i.e., pole or machine sheds) in the Lepanto study plot. Based on casual encoun- ters with owls, this plot appeared to have a high density of Barn Owls (both breeding and nonbreeding individuals) before the nesting structures were erected. However, we had no data pertaining to Barn Owl densities on this plot prior to treatment. The fact that artificial nest structures were exploited in the Lepanto plot, which appeared to have a high number of owls to begin with, suggests that suitable nesting sites in this area may have been limited. On our study area as a whole, however, relatively few nesting structures were occupied by the time we com- pleted field monitoring in December 2001. Also, no sign of use (e.g., pellets) was observed at any of the other structures. It is possible that the local Barn Owl popula- tion was limited by some other environmental factor (e.g., prey availability, juvenile mortality) leading to low occupancy of nest boxes in northeastern Arkansas. Breeding Chronology and Reproductive Success. The mean date of the onset of egg laying for Barn Owls over a 2-yr period in our study area in northeastern Arkansas was 15 February. In comparison, the mean clutch initia- tion date for Barn Owls in Utah was 13 March (Marti 1994). The latter estimate was based on a sample of 295 nesting attempts (first brood) over a 16-yr period. Also in Utah, Looman et al. (1996) reported that most owl pairs attempting first clutches (36%) commenced egg laying in the first half of March, while 25% began in late February. Based on a sample of 100 Barn Owl nests m New Jersey, Colvin (1984) gave 14 April as the mean peak of egg laying. The mean length of the nesting season for Barn Owls in our study was 5.8 mo over the 2 study yr. In comparison, Otteni et al. (1972) reported 5.3 mo over a 7-yr period in south Texas, while Looman et al. (1996) gives 6.6 mo as the mean for a 5-yr study in north-central Utah. Barn Owl nesting success in our study (56%) was similar to Barn Owls in the Chesapeake Bay area of Mary- land (57%; Reese 1972), but slightly lower than that re- ported in south Texas (66%; Otteni et al. 1972). Based on our data, we concluded that Barn Owls m Arkansas produce smaller clutches and fledge fewer young per nesting attempt compared to Barn Owls m most other parts of the world (Table 2). Lower clutch size and reproductive success of owls in Arkansas may be explained, in part, by the well established relationship between latitude and clutch size (Welty and Baptista 1988). However, several investigators (Otteni et al. 1972, Lenton 1984, Wilson et al. 1986) working in areas at con- siderably lower latitudes reported larger mean clutch siz- es than those in our study (Table 2). Likewise, these same investigators reported larger mean clutch sizes than those given by Taylor (1994) in Scotland and Bunn et al (1982) in England. There is evidence in the literature that clutch size and fledging success in Barn Owls are related to prey avail- ability and habitat (both of which can vary locally and temporally) as well as other variables associated with lat- itude. For example, Otteni et al. (1972) reported that the mean clutch size, number of fledglings, and nest success all decreased markedly following a dramatic decline in rodent numbers. Marti and Wagner (1985) found the number of young fledged per pair of Barn Owls in north- ern Utah varied from 3. 6-4.8 until 1982, when it fell to 1.6 following an extremely severe winter that may have reduced local vole populations. In Scotland, Taylor (1994) noted that clutch sizes and fledging success were 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. Geographic Location Latitude Mean Clutch Size (A) Mean No. of Young Fledged Per 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 cover types near the nest site affected clutch size and fledging success. Barn Owl pairs that nested in or near tree plantations produced mean clutch sizes of 5.1 eggs (range = 4. 0-6. 7), whereas those in low farmland yielded mean clutches of 4.0 eggs (range = 3. 0-6.0), but differ- ences between areas were greatest in vole peak years (Taylor 1994). Thus, in Scotland it would appear that cover type affects prey availability, which in turn, influ- ences Barn Owl productivity. In light of these findings, the poor nest productivity we recorded for Barn Owls in northeastern Arkansas may be due to a relatively low prey base resulting from drought-like conditions that the state had been under for the better part of our study (S. Culp, Craighead County Extension Office, pers. commun.). However, we have no data on local prey availability or abundance for the 2 yr of our study to examine these hypotheses, and recom- mend that sampling to determine mammal abundance would be important to understand factors that may influ- ence the variation in reproductive success. Also, our study was relatively short term, and it is likely that Barn Owl productivity in northeastern Arkansas may fluctuate over the long term with variations in prey populations. Additional data, collected over more years of study, would be needed to evaluate this possibility. Finally, because most of the nests in our study were in some form of nest box, our data may not be directly comparable to studies involving natural nest locations (i.e., tree cavities). Uso DE Estructuras de Nidificacion Artificiales y Exito Reproductivo de Tyto alba en el Noreste de Arkansas Resumen. — Colectamos datos sobre el uso de cavidades de nidificacion por parte de Tyto alba y sobre su exito reproductivo en el noreste de Arkansas durante 2000—01 Se delinearon ocho parcelas de estudio (cada una de 100 km^) que incluian principalmente cultivos de arroz, trigo de invierno, soya y algodon. Aleatoriamente, cuatro de estas parcelas fueron designadas como controles y cuatro como areas “manipuladas”, en cada una de las cuales se erigieron 12 estructuras de nidificacion (A = 48 estruc- turas) entre enero y marzo de 2000. Una de las estruc- turas fue ocupada como percha dormidero por un indi- viduo en junio de 2000 y cuatro (8.3%, N= 48) fueron ocupadas por individuos nidificantes en marzo de 2001. Encontramos 27 nidos tanto dentro como fuera de las parcelas de estudio, de los cuales 14 estuvieron en las parcelas manipuladas (x = 3.5 nidos/ parcela) y tres en las parcelas control (x = 0.75 nidos/parcela). De 14 m- dos salieron un total de 38 pichones, 10 nidos fracasaron y el destino de tres no fue determinado. La fecha pro- medio de iniciacion de la postura por parte de T. alba en nuestra area de estudio fue el 15 de febrero (mediana = 16 de febrero; rango = 28 de diciembre — 25 de marzo), y la duracion promedio de la estacion de nidificacion, desde el comienzo de la postura de huevos hasta el em- plumamiento del ultimo pichon, fue de 5.8 meses. El tamano de nidada promedio fue 3.8 {N = 17) y el nu- mero promedio de pichones emplumados por nido exi- toso fue 2.7 {N = 14). La productividad de los nidos de T. alba en nuestro estudio fue considerablemente menor que la reportada por otros estudios sobre esta especie realizados alrededor del mundo. El pobre desempeno re- productivo pudo haberse debido a que los tamanos de las poblaciones de presas eran relativamente pequenos debido a las condiciones de sequia sufridas por la region del noreste de Arkansas durante el estudio. [Traduccion del equipo editorial] March 2005 Short Communications 79 Acknowledgments Major funding was provided by the Arkansas Game and Fish Commission and was facilitated by Karen Rowe. Ad- ditional monetary support was contributed by the Arkan- sas Audubon Society Trust. The Keeling Co. of Jones- boro, Arkansas, gave a generous reduction on the price of the PVC pipe necessary to build artificial nesting struc- tures. We thank J.D. Wilhide, V. Hoffman, C.J. George, J. Holt, T. Bader, B. Cannon, M. Cannon, D. Ripper, L. Wilf, M. Barnett, C. McCown, K. Levenstein, L. Alterman, and D. Feldman for assistance in the field. Also, we thank all the landowners who gave us permission and access to their lands. We greatly appreciate the contributions of Eric Forsman, who reviewed an earlier draft of this man- uscript. Lastly, we would like to thank C. Boal, M. Martell, and two anonymous reviewers for their valuable sugges- tions and constructive editing of this manuscript. Literature Cited Bloom, RH. and SJ. Hawks. 1983. Nest box use and re- productive biology of the American Kestrel in Lassen County, California. Raptor Res. 17:9-14. Bunn, D.S., A.B. Warburton, R.D.S. Wilson. 1982. The Barn Owl. Buteo Books, Vermillion, SD U.S.A. Colvin, B.A. 1984. Barn Owl foraging behavior and sec- ondary poisoning hazard from rodenticide use on farms. Ph.D. dissertation, Bowling Green State Univ., Bowling Green, OH U.S.A. De Groot, R.S. 1983. Origin, status and ecology of the owls in Galapagos. Ardea 71:167-182. Duckett, J.E. 1991. Management of the Barn Owl {Tyto alba javanica) as a predator of rats in oil palm {Elaeis guineensis) plantations in Malaysia. Ends Prey Bull. 4: 11-23. Hamerstrom, R, F.N. Hamerstrom, and J. Hart. 1973. Nest boxes: an effective management tool for kestrels. J. Wildl. Manag. 37:400-403. Lenton, G.M. 1984. The feeding and breeding ecology of Barn Owls ( Tyto alba) in peninsular Malaysia. Ibis 126:551-575. 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. Great Basin Nat. 56:73—84. Marti, C.D. 1992. Barn Owl {Tyto alba). In A. Poole, P. Stettenheim, and F. Gill [Eds.], The birds of North America, No. 1. Academy of Natural Sciences, Phila- delphia, PA and the American Ornithologists’ Union, Washington, DC U.S.A. . 1994. Barn Owl reproduction: patterns and var- iation near the limit of the species’ distribution. Con- dor 96:468-484. and P.W. Wagner. 1985. Winter mortality in com- mon Barn Owls and its effect on population density and reproduction. Condor S7\\W— 11b. , , AND K.W. Denne. 1979. Nest boxes for the management of Barn Owls. Wildl. Soc. Bull. 7:145- 148. Mayfield, H.F. 1975. Suggestions for calculating nest suc- cess. Wilson Bull. 87:456-466. Newton, 1. 1979. Population ecology of raptors. T. & A.D Poyser, London, U.K. Otteni, L.C., E.G. Bolen, and C. Cottam. 1972. Preda- tor-prey relationships and reproduction of the Barn Owl in southern Texas. Wilson Bull. 84:434—448. Radley, P.M. 2002. Artificial nest structure use, post- fledging habitat use, and dispersal of Barn Owls {Tyto alba pratincola) in the Delta region of Arkansas. M.S. thesis, Arkansas State Univ., Jonesboro, AR U.S.A. Reese, J.G. 1972. A Chesapeake Barn Owl population. Auk 89:106-114. Taylor, I. 1994. Barn Owls: predator-prey relationships and conservation. Cambridge University Press, Cam- bridge, U.K. Walk, J.W., T.L. Esker, and S.A. Simpson. 1999. Contin- uous nesting of Barn Owls in Illinois. Wilson Bull. 111. 572-573. Welty, J.C. and L. Baptista. 1988. The life of birds. 4th Ed. Saunders College Publishing, New York, NY U.S.A. Wilson, R.T., M.P. Wilson, and J.W. Durkin. 1986 Breeding biology of the Barn Owl {Tyto alba) in cen- tral Mali. Ibis 128:81-90. Received 21 October 2003; accepted 17 November 2004 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- dri; diet, abundance, Boavista; Alexander’s Kestrel, Alexander’s Kestrel {Falco tinnunculus alexandri) is an endemic resident subspecies of the Common Kestrel re- siding on Cape Verde archipelago, characterized by heavily marked upper parts and a barred tail in all plum- ages (Hazevoet 1995), which occurs only on the eastern and southern islands (Sal, Boavista, Maio, Santiago, Fogo, and Brava) . The geographical distribution of the subspe- cies in the archipelago is explained by the effect of the last glaciation, which split the kestrel population into two distinct island groups, with Alexander’s Kestrel to the south and Neglectus Kestrel {Falco tinnunculus neglectus) to the north (Hazevoet 1995). This circumstance caused morphological and ecological differences between the two subspecies of raptors (Hille and Winkler 2000), which are endemic birds scarcely known at present. Alexander’s Kestrel is common on the islands, occu- pying all habitats from sea level up to the highest moun- tains, but information on its biology is lacking. Only its taxonomy, distribution, and breeding dates have been re- ported (Bourne 1955, De Naurois and Bonnaffoux 1969, Stresemann and Amadon 1979, De Naurois 1987, Haz- evoet 1995), but no data are available on its abundance or food habits in the archipelago. Islands offer divergent environments with geographi- cally separated animal populations that are subject to sev- eral evolutionary forces such as genetic bottle-necks, drift, gene flow, and selection driven by local conditions. In this way, the conservation needs of island fauna, and especially of raptors, are generally more urgent than those of continental species, except where limited distri- butions on continents mimic island-like isolation (Virani 1995, Virani and Watson 1998). Therefore, knowledge of an endemic and restricted species such as Alexander’s Kestrel is key to their conservation. In this paper, I present the first data on the relative abundance and diet composition of Alexander’s Kestrel on an island (Boavista), which represents 23.5% of the distribution area of the subspecies in the world. Study Area and Methods The Cape Verde Islands are situated in the eastern At- lantic, between 14°48'-17°22'N and 22°44'-25°22'W, 460-830 km west of Senegal (Fig. 1). The archipelago is ^ Email address: dontive@ugr.es comprised of 10 islands and several islets. Boavista Island extends 620 km®, with ca. 116 km of perimeter, being the third largest island of the archipelago in surface area. Its topography is generally flat; the highest elevation (Monte Estancia) is 387 m. The climate is very dry (mean annual rainfall = 91 mm; Kasper 1987) and the presence of goats causes continued desertification of the land. There- fore, the landscape of the island consists mainly of large areas covered with sand, forming mobile dunes and bar- ren-stony plains, but in the interior there are oases with palms (Sena-Martins et al. 1986). Because the moderat- ing influence of the surrounding ocean temperatures are relatively constant, the amplitude of mean temperatures in different months seldom exceed 6°C. To estimate the abundance of Alexander’s Kestrels on Boavista Island, a driver and an observer performed sev- en line transects (one transect/d) in a vehicle during July 1999, on days of good visibility, travelling at ca. 40 km/ hr, counting (with 10X40 binoculars) all individuals perched or flying closer than 300 m on either side of the road. Transect lengths varied, ranging from 9-55 km (to- tal length = 226 km) according to the availability of ad- equate roads. All censuses were performed on unpaved roads, far from the few existing power lines (potential hunting perches) of the island, these being located in villages; therefore, the data are not biased by this circum- stance. Counting raptors from a vehicle along roads in a flat landscape with scarce vegetation (the case for Boa- vista Island) is a widely used method (Johnson 1978, Ful- ler and Mosher 1981, Byby et al. 2000), particularly for kestrels (Telia and Forero 2000). It provides an abun- dance index that is sensitive to the behaviour of the spe- cies involved, the habitat surveyed, speed of the vehicle, meteorological conditions, hour, season, and number and experience of observers. In the presence of the ob- server, the animal response varies according to different factors (Eberhardt 1978, Burnham et al. 1980). There- fore, in the censuses I considered the detection distance and angle of individuals. Boavista Island has a homoge- neous landscape (desert with some oases), and the length of the line transects were distributed proportion- ally over the surface of these habitats. I estimated the density of Alexander’s Kestrel on the island with the pro- gram DISTANCE 4.1 (Thomas et al. 1998) and empiri- cally calculated the variance. Also, I studied the food habits of this raptor in July, analyzing 44 pellets collected under eight different roost- ing sites. Due to the scarce number of bird species on the island (see Discussion), avian prey were identified from feather remains when possible, reptiles from skulls and mandibles collected from the study area, mammals from hair remains (Teering 1991) , and insects from head capsules and mandibles. The biomass contribution of each species in the total biomass was estimated following 80 March 2005 Short Communications 81 100 km Boavista Island o Figure 1 . Map of Cape Verde Islands, and their position relative to West Africa. Marti (1987), assigning the biomass of birds from Cramp (1998), and using mass data from individuals of the study area for other prey. Results and Discussion Analysis of the data collected with program DISTANCE showed a mean density of 0.125 Alexander’s Kestrels/ km^ (95% C.I. = 0.045-0.348 kestrels/km^), implying an estimated population of 77 individuals (95% C.I. = 28- 216 kestrels) of Alexander’s Kestrel for Boavista Island. However, I only detected seven kestrels (one male and SIX females), thus the estimated density must be consid- ered as a very course estimate. Burnham et al. (1980) suggested that at least 40 detections were required to de- termine adequate density estimates using line transects techniques. Most young Alexander’s Kestrels leave their nests in April (Hazevoet 1995), 3 mo before the censuses were performed (July). Therefore, the young were likely uni- formly distributed throughout the island. Thus, the total breeding population might be lower than the numbers estimated during my surveys. Nevertheless, the limited 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- trels were invariably located in areas with trees, buildings or small cliffs, and were never found in areas without perch and roost habitat. The availability of elevated 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 biomass consumed by Alexander’s Kestrel. This small liz- 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 other studies that have reported 12.01 g as a mean bio- mass of prey caught by Common Kestrels (Piatella et al. 1999). Boavista Island has a homogeneous semiarid cli- mate throughout the year (Kasper 1987) and the lizards are active all year. Thus, this prey item may be important in other seasons, as well as in July when I collected pel- lets. Several factors can explain the stenophagy of Alexan- der’s Kestrel on the Mabuya Skink on Boavista Island. (1) Only between 17-23 species of birds breed on the island (Hazevoet 1995), nine of which are smaller than Alex- ander’s Kestrel, thus being potential prey. (2) Among reptiles, only two species of marine turtles and four liz- ards are present on the island (Lopezjurado et al. 1999), but three of the lizards are nocturnal ( Tarentola and Hem- idactylus) and only the skink is diurnal, and may be the primary prey of the kestrel. (3) As expected for an oce- anic island, no indigenous terrestrial mammals inhabit the Cape Verde Archipelago, and only the exotic Mus musculus and Rattus spp. are present (Hazevoet 1995), Table 1. Dietary composition of the Alexander’s Kestrel on Boavista Island (Cape Verde). Prey Frequency N{%) Biomass 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 as Boavista. (4) Finally, the sparse vegetation of the island does not support great numbers of invertebrates, which therefore barely appear in the diet of the kestrel. Con- sequently, the only prey species on Boavista Island that is largely abundant, a ground dweller, appropriate in size, and exhibits diurnal activity is the skink. The pellet data clearly supports that the skink is the most common prey of the Alexander’s Kestrel in July (Table 1). Nevertheless, the more easily digested prey, such as invertebrates, are often underrepresented in pellets (Mersmann et al. 1992, Whalen et al. 2000) and therefore may be underrepre- sented in my results as well. Many ecomorphological studies have shown the close relationship between habitat and behaviour of birds (Leisler et al. 1989, Gamauf et al. 1998, Hille and Winkler 2000) , and as ground-level vegetation can affect the abil- ity to detect prey, this factor may influence the success of particular foraging behaviours (Bechard 1982, Janes 1985). Therefore, the broad deforestation of Boavista Is- land and the absence of alternative prey could account for the high kestrel use of this .swift, but abundant, skink. Despite the limited sample size of this study, no other studies on food habits of Alexander’s Kestrels in Cape Verde archipelago are available. Except for the re.sults of this study, lizards have been reported as scarce prey in the diet of the Common Kestrel throughout the western Palearctic (Cramp 1998). These results contradict the prediction of Hille and Winkler (2000), who found that the larger bill and long- er wing of Alexander’s Kestrel may indicate frequent ae- rial hunting of larger prey items than those sought by the Neglectus Kestrel. Nevertheless, aerial hunting is more energetically expensive and is employed in areas where climatic and topographic conditions are conducive to such foraging, or when prey availability is high enough to yield a positive energy budget (Barnard 1986, van Zyl 1993) . In support of this hypothesis, , a comparison of the diet of kestrels between South Africa and Europe showed that the African population consumed mostly inverte- brates and lizards and only few mammals and birds, rath- er than the opposite as observed in Europe (van Zyl 1994) . The Cape Verde Islands are oceanic islands with a re- cent volcanic origin, and consequently have flora and fauna derived from elsewhere. Oceanic islands are often isolated laboratories on which their populations gave rise to a marked radiation of different species. Contrary to other islands widely studied, such as the Galapagos ar- chipelago, the avifauna of Cape Verde is poorly known. The lack of study is especially troubling, because the oc- currence of Palearctic taxa in the Cape Verde is of con- siderable interest. These are the southernmost and most isolated breeding populations of some Palearctic species, being some 2000 km from their nearest congeners in North Africa and Southern Europe (Hazevoet 1995). For almost 40 yr, scientists and naturalists have called for measures to preserve the rapidly declining populations of seabirds and endemic land birds of Cape Verde Islands (e.g., De Naurois 1964, Norrevang and Hartog 1984, Har- tog 1990, Donald et al. 2003). The stenophagy of the Alexander’s Kestrel, the scarcity of elevated perches and roosts, and the progressive deforestation of Boavista Is- land, could affect the current status of this subspecies on Boavista Island. AbUNDANCIA Y DiETA de FaLCO riNNUNCULUS ALEXANDRA EN Lsla Boavista (Archipielago de Cabo Verde) Resumen. — El cernicalo Falco tinnunculus alexandri es una subespecie de cernicalo comun, endemica del Archipie- lago de Cabo Verde y escasamente conocida. En este ar- ticulo se presentan los primeros datos sobre abundancia y alimentacion de la rapaz en el archipielago, concreta- mente de la poblacion de la Isla de Boavista. Para su estudio se han recorrido un total de 226 km de transectos lineales, cifrandose la poblacion de la especie en Boavista en 0.125 individuos/km^ (95% I.C. = 0.045-0.348 indi- viduos/km^) , unos 77 individuos, si bien hay que tomar la cifra con precaucion ante lo reducido de la muestra obtenida. En la dieta de la rapaz unicamente se encon- traron seis tipos de presas distintas, debido probable- mente a la deforestacion general de la isla y escasa dis- ponibilidad de recursos troficos. Su dieta se baso fundamentalmente en el consumo de Mabuya spinalis sal- ensis, un escincido endemico de la isla que represento hasta el 84.7% de la biomasa comsumida por el cernicalo. La acusada estenofagia de esta especie y la creciente es- casez de perchas en la isla, podrian ser una amenaza para el future de la poblacion del cernicalo F, tinnunculus al- exandri en esta isla. [Traduccion de los autores] Acknowledgments I wish to thank J.M. Pleguezuelos and two anonymous referees for reviewing the original manuscript and pro- viding valuable suggestions, J.A. Mateo for mass data for specimens, and L.E Lopezjurado, F. Pascual, and the people of Boavista for their kind help during this study. Literature Cited Barnard, P. 1986. 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Raptor Res. 39(l):84-88 © 2005 The Raptor Research Foundation, Inc. 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, plumage, feather, molt. In a prior study (Quinn et al. 2002) , we examined the effects of Aroclor 1242 (a mixture of polychlorinated bi- phenyls [PCB]) on feather production in the American Kestrel {Falco sparverius) . The development of plumage is heavily influenced by the action and timing of thyroid hormones (Owens and Short 1995, Kuenzel 2003). Al- though Aroclor 1242 was shown to cause decreases in plasma thyroxine (Quinn et al. 2002), no significant dif- ferences were observed in feather production or appear- ance between PCB and control treatments. The data pre- sented here illustrate the relative roles of thyroxine on molt and plumage pigmentation in the American Kestrel. Although it is well known that molt and feather re- growth are dependent on thyroid hormones, the under- lying mechanisms remain unclear. Experimentally-admin- istered thyroid hormones typically induce molt, and normal schedules of molt and feather regrowth are as- sociated with changes in thyroid hormones (Kuenzel 2003). Sequence of molt also is modulated by thyroid hormones (Payne 1972). Feather loss and regrowth oc- curs in a regular sequence along each feather tract. Pat- terns in thyroxine-induced molts may depart from the orderly sequence of feather replacement observed in nat- ural molts. The melanin content and structure of bar- bules in feathers, that would affect feather color and pat- terns, also can be altered by high levels of circulating thyroid hormones (Payne 1972). The timing and quality of feather loss and regrowth can affect many aspects of a bird’s life. Thermoregulation and flight can be significantly affected by changes in plumage production (Dawson et al. 2000). Feathers also communicate mate quality and age in a number of spe- cies. The plumage colors and patterns measured in this ^ Email address: mquinn@umd.edu study are important secondary sexual characters for the American Kestrel (Wiehn 1997a, 1997b). The objectives of this study were to: (1) investigate the roles of thyroid hormones in molt in American Kestrels, and (2) deter- mine the relative roles of thyroxine in plumage pigmen- tation. Methods American Kestrels used in this study were 1-yr-old off- spring from a captive colony at the U.S. Geological Sur- vey Patuxent Wildlife Research Center (Laurel, MD). Pairs were randomly assigned to flight cages measuring ca. 24 X 4 X 6 m. Seven pairs of kestrels per treatment received food that was treated with either 10 ppm thy- roxine (3, 3', 5, 5' tetradiodo-L-thyroxine free acid) or 2000 ppm propylthiouracil (6-n-propyl-2-thiouracil) , a thyroid hormone blocker (Sigma Chemical Co., St. Lou- is, MO U.S.A.). Treatment levels were chosen to be non- lethal, but above estimated no-observed-effects levels (May 1980, Leung et al. 1985, Lien et al. 1987, Kai et al 1988, Slopes 1997, al-Afaleq and Homeida 1998). Chem- icals were mixed with rice flour, and the resulting mix- ture was added to the kestrels’ standard diet of horse- meat (Nebraska Brand Bird-of-Prey Diet, Central Nebraska Packing, North Platte, NE U.S.A.). Rice flour constituted 1% of the final mixture; therefore, six pairs of kestrels received the control diet of horsemeat with flour and without chemicals at 1%. Treated food was giv- en ca. 1 wk before egg laying began (second week of June) and ended when the birds finished molting in the fall (second week of October). Each kestrel was fed two 2.0 g treated horsemeat balls daily from Monday through Friday and two untreated mice on Saturday. They were fasted on Sunday to help ensure hunger for the treated food. We collected the outermost secondary-flight feathers from the right wing and the second rectrix from the mid- dle on the right side of the tail from each male and fe- male after they had regrown under treatment. Feather position was numbered according to Willoughby (1966) 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 measurements were recorded from 230-800 nm at 1 nm intervals. A 3 X 10 mm diameter spot on each area of color was presented flat against the aperture of the spec- trophotometer, with the vane perpendicular to the beam of light. Data consisted of reflectance calculated as a per- centage of light reflected from a standard white block of vitrolite, a near-flawless diffusing surface. Reflectance measurements were conducted at the National Institute of Standards and Technology, Gaithersburg, MD. The progress of molt for primaries and retrices was recorded weekly by capturing each bird and recording feathers lost and the length of growing feathers. Timing of molt was measured by date of onset and total duration of molt. Date of molt onset is the date when the first primary feather dropped. The duration of molt was mea- sured as the interval between the onset of molt and the complete regrowth of the last rectrix. The sequence of molt was averaged within treatment groups for each pri- mary and rectrix and compared to sequences recorded by Willoughby (1966). Approximately 1.0 ml of blood was collected weekly from the jugular vein using a syringe rinsed with a sodi- um heparin solution. Each sample was centrifuged, and the plasma was collected and stored at — 70°C. Plasma thyroxine was measured in duplicate samples with a dou- ble antibody radioimmunoassay (RIA; Wilson and Mc- Nabb 1997). We validated the RIA for hormone mea- surements on kestrel plasma by demonstrating parallelism of the standard curve and diluted and hor- mone-spiked samples of kestrel plasma. Sensitivity was 12.5 |jl1 and precision, as coefficient of variation, was 3.1%. Data on reflectance were averaged for every 100 nm from 800-400 nm (visual range) and analyzed by multi- variate analysis of variance (MAN OVA). Data from 399— 230 nm (UV range) were analyzed separately by two-way analysis of variance (ANOVA). Plasma-thyroxine levels were analyzed by analysis of covariance with week of sam- ple collection as the covariate to account for possible Treatment Figure 1. Width (mm) of subterminal bands on the re- trices of male American Kestrels treated with 10 ppm thy- roxine or 2000 ppm propylthiouracil. Error bars are stan- dard errors of the mean. V = 7 for the thyroxine and propylthiouracil treatments and 6 for the control treat- ment. Means labeled as “A” are significantly different than those labeled as “B.” time differences. All other data were analyzed by two-way ANOVA. Data were analyzed separately by sex for sexu- ally-dimorphic characters and when sex-by-treatment in- teractions were significant. Tukey tests were used for post hoc pairwise comparisons. Statistical computations were performed using SPSS for Windows, Version 8.0 (SPSS 1998). Results There was no overall effect of treatments on plumage color as measured by the Munsell color scores. However, treatments did have a significant effect on the width of the subterminal bands on male retrices (Fig. 1; P= 0.02). Subterminal bands from thyroxine-treated birds were ca. 4 mm wider than those from control (P = 0.038) and PTU (P = 0.008) treated birds. Reflectance of feather colors did not differ significantly among males of different treatments in the visual range, and only marginal differences existed for males in the ultraviolet range (P = 0.07). However, there were signif- icant treatment differences between reflectance for fe- males (Fig. 2) in the visual (P = 0.004) and the ultravi- olet ranges (P = 0.019). Feathers from thyroxine-treated birds were significantly more reflective of light of wave- lengths from 400-700 nm (400-499 nm: P < 0.05; 500- 599 nm: P < 0.05; 600-699 nm: P < 0.05) and only mar- ginally more reflective from 700-800 nm (P = 0.057). 86 Short Communications VoL. 39, No. 1 Wavelength (nm) Control Wavelength (nm) Thyroxine Wavelength (nm) Pi'opyltliioiu'acil Figure 2. Reflectance of feathers in the visual (400-800 nm) and ultraviolet (230-399 nm) ranges from female American Kestrels treated with 10 ppm thyroxine or 2000 ppm propylthiouracil. N = 4 for the thyroxine treatment, 6 for the propylthiouracil treatment, and v5 for the con- trol treatment. Mean reflectance from graph labeled as “A” was significantly different than graph labeled as “B.” 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 er- rors of the mean. N = 7 for the thyroxine and propyl- thiouracil treatments and 6 for the control treatment Means labeled as “A” are significantly different than that labeled as “B.” 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) treat- ments. 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 ob- served by Willoughby (1966). Although the sequence of molt for the retrices did not differ among treatments, slight differences were observed between all our treat- ment groups and Willoughby’s birds in the sequence of molt of the last three retrices. However, the variations m our observed molt sequences did not deviate from the natural pattern of variability originally described by Wil- loughby. Hormone assays confirmed clearly the effects of the thyroxine treatment on plasma thyroxine concentrations in both males and females from the second to the fifth week of treatment (P< 0.0001; Fig. 4). Plasma thyroxine concentrations from PTU-treated kestrels were consis- tently lower than controls; however, these differences were not significant. Discussion The goals of this research were to determine the rel- ative roles of thyroxine in plumage pigmentation and molt in American Kestrels. The observed changes in March 2005 Short Communications 87 I (as 1 2 3 4 5 Weeks After Treatment Weeks After Treatment Figure 4. Mean (±SE) plasma thyroxine concentrations (ng/ml) in male (A) and female (B) American Kestrels treated with 10 ppm thyroxine or 2000 ppm propylthi- ouracil. Error bars are standard errors of mean. N = 7 for the thyroxine and propylthiouracil treatments and 6 for the control treatment. 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- duction. A possible explanation of our results is that the onset of molt may only require a threshold level of thy- roxine that may have been exceeded in all of the treat- ments. 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 sequence, Payne (1972) suggested that the pattern of feather loss and regrowth may be altered in thyroxine- 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 fac- tors 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 thyrox- ine modulated plumage production in American Kes- trels; however, it appeared that other unidentified factors may have played stronger roles in this process. More stud- ies are needed to explore the individual roles and inter- actions of the myriad of signals that are involved with feather loss and regrowth. PaPEL DE I a TiROSINA EN la PrODUCCION DEI. Plumaje en Falco sparverius feather pattern and reflectance in thyroxine-treated birds suggest an influence of thyroxine on feather pigmenta- tion. No such alterations were observed in the PTU-treat- ed birds, suggesting that although thyroid hormones modulate certain aspects of molt and feather production, other hormones may also play a role. Estradiol, testoster- one, and prolactin also have strong effects on feather loss and regrowth (Vevers 1962, Nolan et al. 1992, Dawson and Sharp 1998). Clearly more studies are needed to bet- ter understand the hormonal interactions in this com- plex process. Our data suggest that thyroxine may not play as signif- icant a role in the American Kestrel for initiation of molt as in other species. Although the onset of molt was un- affected by treatments, thyroxine decreased the amount of time required to complete a molt. Dawson et al. (2000) state that in most birds, onset of molt is most heavily influenced by termination of breeding and that rate of molt is more affected by seasonal changes in day length. Longer day lengths combined with increased lev- els of thyroxine play a stronger role in implementing re- fractoriness to reproduction (Wilson and Reinert 1996, Resumen. — ^Aunque es sabido que el desarrollo del plu- maje es modulado en parte por la accion de las hormo- nas tiroideas, se sabe poco sobre el grado al cual estas hormonas controlan la perdida y reemplazo de las plu- mas y la pigmentacion en las aves rapaces. En este estu- dio, halcones de la especie Falco sparverius recibieron ah- mento tratado con 10 ppm de tirosina o con 2000 ppm de propiltiouracilo (PTU, un bloqueador de la tiroides) diariamente desde una semana antes de que comenzara la puesta de huevos hasta el final de la muda. La dura- cion de la muda de las plumas de vuelo fue significati- vamente mas corta en halcones que recibieron tirosina La aparicion de las plumas fue evaluada midiendo el co- lor (utilizando una carta de colores de referenda), la reflectancia de 230-800 nm y el ancho de la banda sub- terminal de la cola del macho. Los halcones tratados con tirosina tuvieron bandas terminales significativamente mas anchas. Las plumas de hembras tratadas con tirosina presentaron valores de reflectancia significativamente mayores, tanto dentro del rango visual como del ultra- violeta, que las hembras que recibieron PTU. [Traduccion del equipo editorial] 88 Short Communications VoL. 39, No. 1 Acknowitdgments We are thankful for the guidance of Yvonne Barnes at the National Institute of Standards and Technology with the reflectance measurements. We are also grateful for the help and guidance of Greg Paulson and Tim Maret at Shippensburg University and the helpful suggestions of the Journal of Raptor Research referees. This work was funded in part by EPA Star Grant No. R-82'7400-01-0. Literature Cited al-Afaleq, A.I. and A.M. Homeida. 1998. Effects of low- doses of oestradiol, testosterone, and dihydrotestos- terone on the immune response of broiler chicks. Im- munopharmacol. Immunotoxicol. 20:315—327. Berry, W.D. 2003. The physiology of induced molting. Poult. Sci. 82:971-980. Dawson, A., S.A. Hinsley, P.N. Ferns, R.H.C. Bonser, AND L. Eggleston. 2000. Rate of molt affects feather quality: a mechanism linking current reproductive ef- fort to future survival. Proc. R. Soc. Lond. 267:2093- 2098. AND PJ- Sharp. 1998. The role of prolactin in the development of reproductive photorefractoriness and postnuptial molt in the European Starling (Sturnus vulgaris). Endocrinology 139:485-490. Kai, O., H. Nagase, N. Ishikawa, M. Suzuki, T. Kakega- WA, AND K. Sato. 1988. Effects of propylthiouracil (PTU) on the immunological status of the chicken. Dev. Comp. Immunol. 12:145-156. Kuenzel, W.J. 2003. Neurobiology of molt in avian spe- cies. Poult. Sci. 82:981-991. Leung, F.C., J.E. Tayi.or, and A. Van Iderstine. 1985. Effects of dietary thyroid hormones on growth, plas- ma T3, and T4, and growth hormone in normal and hypothyroid chickens. Gen. Comp. Endocrinol. 59:91- 99. Lien, R.J., J.R. Cain, and S.L. Beasom. 1987. Effects of dietary and parental estrogens on bobwhite repro- duction. Poult. Sci. 66:154—161. Macbeth. 1994. Munsell soil color chart. Macbeth Divi- sion of Kollmorgen Instrument Corporation, New Windsor, NY U.S.A. May, J.D. 1980. Effect of dietary thyroid hormone on growth and feed efficiency of broilers. Poult. Sci. 59: 888-892. Noian V., Jr., E.D. Ketterson, C. Ziegenfus, D.P. Cul- len, AND C.R. Chandler. 1992. Testosterone and avi- an life histories: effects of experimentally elevated tes- tosterone on prebasic molt and survival in male Dark-eyed Juncos. Condor 94:364—370. Owens, I.P.F. and R.V. Short. 1995. Hormonal basis of sexual dimorphism in birds: implications for new the- ories of sexual selection. Trends Ecol. Evol. 10:44—47. Payne, R.B. 1972. Mechanisms and control of molt. Pages 103-155 in D.S. Earner and J.R. King [Eds.], Avian biology. Academic Press, New York, NY U.S.A. Quinn, M.J., Jr., J.B. French, Jr., F.M.A. McNabb, and M.A. Ottinger. 2002. The effects of polychlorinated biphenyls (Aroclor 1242) on thyroxine, estradiol, molt, and plumage characteristics in the American Kestrel {Falco sparverius). Environ. Toxicol. Chem. 21’ 1417-1422. Siopes, T. 1997. Transient hypothyroidism reinitiates egg laying in turkey breeder hens: termination of photo- refractoriness by propylthiouracil. Poult. Sci. 76:1176— 1782. SPSS Inc. 1998. SPSS base 8.0 for Windows user’s guide SPSS Inc., Chicago, IL U.S.A. Vevers, H.G. 1962. The influence of the ovaries on sec- ondary sexual characters. Pages 263-289 in S. Zuch- erman [Ed.], The ovary. Academic Press, New York, NY U.S.A. Wiehn, J. 1997a. Plumage characteristics as an indicator of male parental quality in the American Kestrel. J. Avian Biol. 28:47-55. . 1997b. Mate choice and reproductive success m the American Kestrel: a role for blood parasites? Ethol- ogy 103:304-317. Willoughby, E.J. 1966. Wing and tail molt of the sparrow hawk. Auk 83:201-206. Wilson, C. and F.M.A. MgNabb. 1997. Maternal thyroid hormones in Japanese Quail eggs and their influence on embryonic development. Gen. Comp. Endocrinol. 107:153-165. Wilson, F.E. and B.D. Reinert. 1996. The timing of thy- roid-dependent programming in seasonally breeding male American Tree Sparrows {Spizella arbored). Gen Comp. Endocrinol. 103:82—92. Received 27 June 2003; accepted 6 October 2004 J. Raptor Res. 39(l):89-92 © 2005 The Raptor Research Foundation, Inc. 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; nest structure, nestling, nesting biology, southeastern Brazil. The Gray-headed Kite {Leptodon cayanensis) occurs in lowland tropical forests from the Amazon region, west to Ecuador, north to the Guianas and Trinidad, and south- ern Tamaulipas and Oaxaca, Mexico (del Hoyo et. al 1994). This raptor is characterized by a gray head, black- ish back, white chest and legs. It ranges in length from 46-54 cm, and has a mass between 416-643 g (Brown and Amadon 1989, Thorstrom 1997). Current knowledge about this species is mostly anecdotal, with the exception of a description of nests and behavior in Guatemala (Thorstrom 1997). We studied this species in southeast- ern Brazil, where in Brazil, Gray-headed Kites were prob- ably restricted to the Amazon basin (Sick 1997). In this paper, we present new information on the eggs, nests, nesting behavior, and diet of the Gray-headed Kite. Study Area and Methods We collected data from July 1999-September 2001 in two different areas and cover types. The first study site (19°2TS, 44°12'W) was in the municipality of Sete La- goas, ca. 60 km north of Belo Horizonte. The mean an- nual rainfall is 1328.7 mm, and the mean annual tem- perature ranges from 15.6-28.2°C. The altitude of the site varies between 700-900 m. This area is characterized by pasture containing some small forest fragments. Al- most all the forest habitat of this region has been con- verted to pastures. The second site (20°02'S, 43°59'W) was located in Belo Horizonte, in a protected area called APE (environmental protection area), located in the Bar- reiro district, which belongs to the sanitation company of Minas Gerais (COPASA-MG). The mean annual rainfall is 1300 mm, and the mean annual temperature ranges from 18— 24°C. The altitude of the site varies between 850-950 m. The cover type at this site consists of a Cer- rado complex and riparian forests. The composition of a Cerrado biome consists of species such as cagaita tree {Eugenia dysenterica ) , pequi tree ( Caryocar brasiliense) , ipe tree {Tabebuia ochracea), macaw palm {Acrocomia aculeate), and araticum tree {Annona crassiflora; Lins and Mendon- ca 2000) In both areas, we searched for all nesting raptors, es- pecially, in forested areas. We observed the three Gray- headed Kite nests that we found as frequently as possible from July 1999-September 2001. Observations were ^ Email address: falconiformes@vsnet.com.br made using 10 X binoculars at distances of 15 m. An ob- 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 We measured eggs with calipers, to the nearest 0.1 mm During 130 hr of observation, we noted adult behavior at and near nests, and recorded prey deliveries. Nestlings were marked with aluminum bands. We could not distm- guisb between the adults on most of the occasions when they visited the nests. Resui.ts We located two nests in 1999 and one in 2001 in two different territories. Nest 1. On 12 September 1999, we observed a Gray- headed Kite building a nest 15 m up in a Copaiba tree {Copaifera langsdorffii) that was 16.5 m tall and 155 cm in diameter breast height (DBH). The nest was 52 m from an occupied Rufous-thighed Hawk {Accipiter erythrone- mius) nest. The habitat around this nest site consisted of Cerrado complex. On our next visit (29 September) , an adult kite was observed incubating. We climbed the nest tree and observed two eggs. The eggs had many conspic- uous dark-brown spots, with a greater concentration of spotting near the base and fading toward the narrow end The eggs measured 50.7 X 40.8 mm and 52.1 X 40.7 mm (Fig. 1). The nest was made of small-diameter twigs and measured 39 X 39 cm across, and was 13.9 cm in depth. The nest cup measured 21 X 22 cm and was 7.5 cm deep On 17 October the first young hatched. It was covered with fluffy white down and had a yellow cere and tarsi, black beak, and a black supraocular stripe. On 14 Novem- ber 1999, nearly one month after hatching, the nestling’s body was covered with white downy feathers and its wing and tail feathers were starting to emerge from the blood sheaths. The cere and feet were brighter yellow than when the chick was younger; the young was banded dur- ing this visit. From the tree blind, we observed adult kites delivering small, dark-colored snakes {N = 6 snakes) m their talons to feed the nestling. The nestling swallowed the snakes whole, making identification difficult. Total observation time at this nest was 56 hr. In this nest, 2 young hatched, but only one fledged. Nest 2. On 14 October 1999, we discovered a second nest, with an adult incubating. This nest was composed of small sticks, 16.5 m above ground in a 17.5 m high in 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 {Accipiter bicolor) nest. On 19 October, we visited the nest and observed two heavily brown-spotted eggs similar to those at the first nest. We could not reach the nest, and therefore, no measurements were taken. On 4 Novem- ber, the pair was still incubating when we visited this site. On 15 November we made another visit to this nest, and found the nest empty and abandoned. The cause of fail- ure may have been a severe rainstorm that moved through the area several days earlier. Total observation time at this nest was 20 hr. Nest 3. On 2 October 2001, we observed a pair of kites on a nest in the same crotch of the same tree where the first nest was located on 12 September 1999 (nest 1). The nest was 63 m from an occupied Rufous-thighed Hawk nest. The nest was constructed with new sticks and mea- sured 40 X 40 cm in diameter and 13.8 cm in depth. The nest cup was 22 X 21 cm and 8 cm deep. The nest held two heavily brown-spotted eggs, which measured 52.0 X 40.7 mm and 51.1 X 40.8 mm. We returned on 2 Novem- ber, when we found two small nestlings, one of them vis- ibly larger than its sibling. They were brown and covered by white down, and their feet and cere were dark yellow with a black supraocular stripe. On 25 November, we again visited the nest and found only one nesding. Its head and back were a mixture of dark gray and black plumage and its chest was white, striped with black. Its cere and feet were dark yellow. This nesding was quite aggressive and attacked us with its feet when we banded it (Fig. 2). On this date, we observed three dark-colored snakes delivered to the nesding by an adult. Based on casual observations, we believe that this pair commonly hunted in the open areas of the Cerrado. The total time of nest observation was 41 hr. Discussion At the three Gray-headed Kite nests that we observed in southeastern Brazil, the breeding season began in Sep- tember with nest construction, incubation began by early to mid October, and young fledged in late November and December. Each of three nests held a two-egg clutch. A one-egg clutch was reported by Thorstrom (1997) in Guatemala, and two and three eggs were reported for two nests of this species by del Hoyo et al. (1994). However, the three-egg clutch reported by del Hoyo et al. (1994) apparendy was erroneous. The original data slips for these three eggs were obtained and examined by D. Whi- tacre (pers. comm.) and these clearly describe three sin- gle-egg clutches. Gray-headed Kites appear to lay a one- to two-egg clutch. Our eggs averaged 51.5 X 40.8 mm, slighdy smaller than the 54.8 X 42.1 mm egg reported from Guatemala (Thorstrom 1997). The smaller egg sizes we found in Brazil may be related to the cost of laying a 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 flimsily constructed in the crotch near the end of a small- diameter branch. The three Brazilian nests, averaged 39.5 X 39.5 cm and the nest cups averaged 21.5 X 22.5 cm and with a depth of 7.8 cm, similar in size to the nest described in Guatemala (Thorstrom 1997). Young Gray-headed Kites fledged with dark pupils, dark gray and black feathers on the head and back, a white chest with vertical dark-brown streaks, white tarsal feathering, and dark-yellow cere and feet. Also, there may be vciriations of the immature plumage (Foster 1971) that we are not able to describe. Gray-headed Kites are reported to feed on many dif- ferent insects, with a fondness for wasp larvae (Hyme- noptera; Haverschmidt 1962, Brown and Amadon 1989), and stomach contents have included remnants of a frog and a bird’s egg (Haverschmidt 1962). The only prey items we observed Gray-headed Kites delivering to nests were nine snakes. Based on the strong odor of two cap- tured adults, Thorstrom (1997) speculated that these kites may feed upon snakes. There has also been a report of a feeding association between Gray-headed Kites and buffy-headed marmosets {Callithrix Jlaviceps', Ferrari 1990). We observed that all three nests were located near to occupied Accipiter nests. Thorstrom et al. (in press) also observed one nest of the Gray-headed Kite 50 m from an occupied Bicolored Hawk {Accipiter bicolor) nest in Gua- temala. The Gray-headed Kite is an uncommon species in the Sete Lagoas area, perhaps due to deforestation. Conser- vation of the remaining forest fragments is likely impor- tant for preserving this and other species dependent on these woodlands for nesting. OBSERVACIONES SOBRE la NlDinCACION DE Leptodon caya- NENSIS EN EL SUDESTE DE BRAZIL Resumen. — Estudiamos individuos de la especie Leptodon cayanensis que se encontraban nidificando entre julio de 1999 y septiembre de 2001. Las observaciones se reali- zaron en dos sitios con diferentes tipos de cobertura: una pradera con parches remanentes de bosque y un bosque ribereno. La construccion de los nidos comenzo en sep- 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 diciembre. Los nidos fueron de construccion endeble y constituidos por ramas secas y se situaron en las bifur- caciones de las ramas de arboles a una altura promedio de 15 m sobre el suelo {N = 3). Las dimensiones pro- medio de los nidos fueron 39,5 X 39.5 cm y 13,9 cm de profundidad exterior, con una copa de 21,5 X 22.5 cm y 7 8 cm de profundidad. El tamano modal de la nidada fue dos {N = 3 nidos) . Los huevos presentaron manchas de color cafe con marcas mas fuertes en la base {N = 6 huevos) y tuvieron un tamano promedio de 51.5 X 40.8 mm (N = 4). Los polluelos eclosionaron de forma asin- cronica. En total, de tres intentos de nidificacion, dos polluelos emplumaron exitosamente, lo que representa un exito de nidificacion del 66.6%. Todas las presas lle- vadas a los polluelos en el nido fueron serpientes (N = 9). [Traduccion del equipo editorial] Acknowledgments We thank Russell Thorstrom for an earlier review of this manuscript, Robson Silva e Silva for supplying ref- erence material and literature, Jane Elce Scheid Ramos for help in the preparation of the manuscript, INMET — National Meteorology Institute (5° Meteorology District) for providing us with climatic data on the first studied area, and Dave Whitacre for his information, references, and review. LriERATURE Cited Brown, L. and D. Amadon. 1989. Eagles, hawks, and fal- cons of the world. The Wellfleet Press, Seacaucus, NJ U.S.A. DEL Hoyo, J., A. Elliott, and J. Sargatal (Eds.). 1994 Handbook of the birds of the world. Vol. 2. New World Vultures to Guineafowl. Lynx Edicions, Barce- lona, Spain. Eerguson-Lee, J, and D.A. Christie. 2001. Raptors of the world. Houghton Mifflin Company, Boston, MA U.S.A. Eerrari, S.E. 1990. A foraging association between two kite species {Ictinia plumbea and Leptodon cayanensis) and buffy-headed marmosets {Callithrix flaviceps) in southeastern Brazil. Condor 92:781— 783. Eoster, M.S. 1971. Plumage and behavior of a juvenile Gray-headed Kite. Auk 88:163—166. Haverschmidt, F. 1962. Notes on the feeding habits and food of some hawks in Surinam. Condor 64:154-158. Lins, L.V. and M.P. Mendonca. 2000. Lista Vermelha das especies ameagadas de extin^ao da flora de Minas Gerais. Publicafoes avulsas da Fundagao Biodiversitas e Funda^ao Zoo-Botanica de Belo Horizonte, Belo Horizonte, Brazil. Sick, H. 1997. Ornitologia Brasileira. Editora Nova Fron- teira, Rio de Janeiro, Brazil. Thorstrom, R.K. 1997. A description of nests and be- havior of the Gray-headed Kite. Wilson Bull. 109:173- 177. , D.F. Whitacre, J. Lopez, and G. Lopez. In press Gray-headed Kite {Leptodon cayanensis ) . /n D. Whitacre [Ed.], Raptors of the Maya Forest: ecology of a trop- ical forest raptor community. Cornell Univ. Press, Ith- aca, NY U.S.A. Received 15 July 2003; accepted 19 September 2004 J Raptor Res. 39(1) :92— 94 © 2005 The Raptor Research Foundation, Inc. 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- tive breeding, polygamy; polygyny; trio. Although monogamy is the most common mating sys- tem among raptors, alternative systems like polygyny, polyandry, and cooperative breeding have been recorded m several species (Newton 1979, Korpimaki 1988, Stacey and Koening 1990). A recent review on the topic showed ^ Email address: ecoljemt@um.es that this was a frequent phenomenon in well-studied spe- cies and that the mating system was probably not deter- mined in many other species because of the difficulty in making appropriate observations and given the fact that many raptors have not been well studied (Kimball et al. 2003). Cooperative breeding has been observed among 3% of bird species, including at least 42 diurnal raptors (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 pairs) of Booted Eagles {Hieraaetus pennatus) in south- March 2005 Short Communications 93 eastern Spain. Our observations were made in 2001 in a mountainous area of the Region of Murcia (southeastern Spain), characterized by large tracts of pine forests {Pinus halepensis) interspersed with smaller clearings of cultivat- ed lands and scrubland. The Booted Eagle is a medium- sized, territorial raptor that nests on trees and rocky cliffs m forested areas of the Palearctic and sub-Saharan re- gions (del Hoyo et al. 1994). This species is considered a monogamous raptor (Newton 1979, Cramp and Sim- mons 1980) and to our knowledge no instances of trios at nests have been reported. In the Iberian Peninsula, Booted Eagles are generally summer residents, arriving from their wintering grounds in late March and early April. In our study area, nest building or reconstruction occurs soon after the eagles arrive and their mean laying date is 24 April. Observations In 2001, during the pre-laying period, a polygynous trio was observed in one territory on the study area. The same territory was monitored in the previous year related to other research. This study in 2000 involved 195 hr of nest observations that allowed us to photograph and in- dividually identify the pair composed of a pale-morph male (Ml) and a dark-morph female (El). This female was trapped and marked with a radiotransmitter mount- ed with a backpack harness. She laid two eggs and the pair reared two young successfully. In 2001, when the trio was recorded, we observed the nest for 46 hr. The male who occupied this nest was the same male observed the previous year (Ml) based on distinctive features of its plumage (blond head and neck, and white breast with numerous brown streaks) . The pre- vious year’s female (El) was identified because of the transmitter. The third bird in the territory was a pale morph individual identified as an adult (the adult plum- age is acquired at the third calendar year; Eorsman 1999) female (F2) due to its size and behavior. No copulations were observed between Ml and either female. Also, dur- ing the pre-laying period, no aggressive interactions be- tween the three individuals were observed. Instead, all three eagles added material to refurbish the nest, al- though the bulk of this task was done by Ml (20%) and FI (70%; N = 10 deliveries of nest material). When the nest was checked on 29 April it was defend- ed by the adults (Ml and FI), and contained two eggs. Both females were observed to incubate the eggs, al- though FI spent more time (93%; N = 540 min) than the accompanying female We also observed the relief of El by F2 from the incubation on three occasions, which occurred when the former left the nest to partic- ipate in territorial defense, to hunt, or apparentiy to take a rest. In contrast, while El incubated, F2 perched on a nearby tree. Although F2 brought greenery to the nest, it was only El who situated the greenery in the nest. During the nestling period, the two hatched young were only fed by FI, while F2 stood perched on a nearby tree most of the time. The helper female (F2) was ob- served only twice with El in the nest. When the male approached the nest with prey, it emitted food-begging calls, which prompted calling from both females. F2 was never observed delivering prey to nest. On one occasion both females attacked a Common Raven {Corvus corax). The pair and the helper female successfully reared one young, who flew for the first time between 5-10 July 2001 Discussion The above described case of apparent polygyny can be considered cooperative breeding because all the mem- bers of the breeding unit contributed to the care of a single nest (Kimball et al. 2003). We suggest that coop- erative breeding in the Booted Eagle is uncommon be- cause of the lack of reports in the scientific literature. Nevertheless, we must be cautious with this affirmation due to the difficulty in observing this kind of behavior, especially for a species with poorly known breeding bi- ology, as is the case of the Booted Eagle (Veiga and Vin- uela 1994, Suarez et al. 2000). The presence of helpers at raptor nests has been as- sociated with many factors, including productive habitats with abundant food supply (Van Kleef and Bustamante 1999), low prey densities (Doyle 1996), biased sex ratio in adults (Oring 1986, Arroyo and Garza 1986), the re- duced availability of suitable sites for reproduction (He- redia and Donazar 1990, Bertran and Margalida 2002), saturation of breeding territories (Heredia and Donazar 1990), potential benefits of group living (Garcelon et al. 1995, Kimball et al. 2003) and benefits to yearlings that gain breeding experience (Zuberogoitia et al. 2003). The Booted Eagle is a philopatric species (Cramp and Sim- mons 1980), thus a possible explanation is that the help- er was an individual born in the study area some years ago and returned to its natal area for the first time. Whether the helper was recruited by the adults to assist with the breeding effort or was a previous offspring of the pair was unknown. Based on our limited observa- tions, it was unclear which factors may have led to this cooperative breeding event. We encourage other observ- ers working on Booted Eagles to make an effort to rec- ognize individual breeders and that researchers should be aware of the possibility of cooperative breeding in this species. Reproduccion Cooperativa por UN Trio en Hieraaetus PENNATUS Resumen. — En esta comunicacion se describe un caso de reproduccion cooperativa por un trio poliginico de Hi- eraaetus pennatus en una zona forestal del sureste de Es- pafia. El trio, observado en 2001, estaba compuesto por un macho de fase clara, una hembra consorte de fase oscura, y una hembra acompanante de fase clara. No se observaron copulas. Ambas hembras colaboraron en las tareas de mantenimiento, incubacion y defensa del nido 94 Short Communications VoL. 39, No. 1 Sin embargo, la hembra consorte contribuyo mucho mas en las actividades reproductivas que la hembra acompah- ante; esta ultima no fue nunca observada trayendo presas al nido o cebando a los polios con el alimento aportado por el macho. [Traduccion de los autores] Acknowledgments We are indebted to Gines Gomez and Martina Carrete for field assistance. We also thank Beatriz Arroyo, Javier Balbontin, Jim Bednarz, and one anonymous referee for helpful comments on the manuscript. Literature Cited Arroyo, B. and V. Garza. 1986. Estudio sobre la situacion del aguila real Aquila chrysdetos en el sistema central. Bol. Est. Cent. Ecol. 30:93—104. Bertran, J. and a. Margalida. 2002. Social organization of a trio of Bearded Vultures ( Gypaetus barbatus) : sex- ual and parental roles. J. Raptor Res. 36:66-69. Brown, J.L. 1987. Helping and communal breeding in birds. Princeton Univ. Press, Princeton, NJ U.S.A. Cramp, S. and K.E.L. Simmons. 1980. The birds of the western Palearctic. Vol. 2. Oxford Univ. Press, Oxford, U.K. DEL Hoyo, J., A. Elliott, and J. Sargatai.. 1994. Hand- book of the birds of the world. Vol. 2. Lynx Edicions, Barcelona, Spain. Doyi.e, F.I. 1996. Bigamy in Red-tailed Hawks in south- western Yukon. / Raptor Res. 30:38-40. Forsman, D. 1999. The raptors of Europe and the Middle East: a handbook of field identification. T. & A.D. Poy- ser, London, U.K. Garcelon, D.K., G.L. Slater, C.R. Danilson, and R.C. 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 polyandrous trios in an endangered population of Lammergeiers Gypaetus barbatus in northern Spain. Biol. Conserv. 53:163—171. Kimball, R.T., P.G. Parker, and J.C. Bednarz. 2003. The occurrence and evolution of cooperative breeding among the diurnal raptors (Accipitridae and Falcon- idae). Auk 120:717-729. Korpimaki, E. 1988. Factors promoting polygyny in Eu- ropean birds of prey — a hypothesis. Oecologia77:278- 285. Newton, I. 1979. Population ecology of raptors. T. & A.D. Poyser, London, U.K. Oring, L.W. 1986. Avian polyandry. Pages 309-351 mR.F Johnston [Ed.], Current ornithology. Plenum Press, New York, NY U.S.A. Stagey, P.B. and W.D. Koening (Eds.). 1990. Cooperative breeding in birds: long-term studies of ecology and behavior. Cambridge University Press, Cambridge, U.K. Suarez, S., J. BalbontIn, and M. Ferrer. 2000. Nesting habitat selection by Booted Eagles Hieraaetus pennatus and implications for management. / Appl. Ecol. 37 215-223. Van Kleef, H. and J. Bustamante. 1999. First recorded polygynous mating in the Red Kite {Milvus milvus) . J Raptor Res. 33:254-257. Veiga, J.P. and j. Vinueia. 1994. Booted Eagle Hieraaetus pennatus. Pages 182-183 in G.M. Tucker and M.F. Heath [Eds.], Birds in Europe: their conservation sta- tus. BirdLife International, Cambridge, U.K. ZuBEROGOiTiA, I., J.A. MartInez, A. Azkona, A. Iraeta, I. Castillo, R. Alonso, and S. Hidai.go. 2003. Two cas- es of cooperative breeding in Eurasian Hobbies. / Raptor Res. 37:342-344, Received 6 October 2003; accepted 27 July 2004 /. Raptor Res. 39(l):94-97 © 2005 The Raptor Research Foundation, Inc. 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 and sparse woodland. Some 181 species of birds have ^ Email address: Nijman@science.uva.nl 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- land is ornithologically relatively well explored, the num- ber of new migrants recorded on the island is still in- creasing (e.g., Prins and Debrot 1996). Two species of raptors breed on the island, and an additional three species are regular nonbreeding visitors (Voous 1982, 1983, 1985). Resident raptors have been studied infrequently. The migrants have not been sub- jected to any systematic observations (Voous 1957, 1982), nor is there a monitoring scheme in place. As such, Bon- aire is typical for the region for which Zalles and Bildstein (2000) commented “With few watch-sites, movements of raptors in (the Caribbean) are decidedly less well under- stood than they are farther north in the Western Hemi- sphere. As a result, (the region) ranks as the least studied region in the world in this regard.” Furthermore, spatial and temporal variation in the abundance of migrant rap- tors in the tropics has been rarely quantified (Thiollay 1978, Nijman 2001), largely because few monitoring pro- grams are in place. We compiled information on the avi- fauna of Bonaire. Our aim was to provide details on the species composition of migrant raptors on Bonaire and to analyze their timing and abundance on the island. Methods Data on the occurrence of raptors in the Netherlands Antilles were compiled from: (1) the collections of the Zoological Museum Amsterdam (ZMA) and Naturalis Leiden (RMNH); (2) records from the archives of the late K.H. Voous and the late Brother Candius van der Linden (both stored in the ZMA) , of whom the latter was resident on Bonaire from 1967-95; and (3) data solicited from ornithologists and observers on the island. Tem- poral distribution of the occurrence of migrant raptors was very similar in these three data sets, so we pooled them for further analysis. We define Bonaire as the island of Bonaire and the islet of Klein Bonaire, but we do not include Isla las Aves situated ca. 60 km to the east. Given that for many of the migrants arriving in the Netherlands Antilles we have no data on their specific breeding lo- calities, following Voous (1983) we define migrant in its broadest sense and include all species that do not have a resident breeding population on Bonaire. We used x^- tests to evaluate differences in the temporal distribution of records by comparing monthly totals. Means are re- ported ± 1 SD and significance is assumed when P < 0.05 in a two-tailed test. Results We compiled 202 records for six species of migrants on Bonaire (Table 1). The mean number of records was 16.8 (±10.2) per mo or 33.7 records (±36.0) per species On average, 3.3 (±1.0) species of migrant raptor per mo are present on the island, ranging from 2-5. The records were not equally distributed over the year, and most mi- grants were observed during the boreal winter (x^ = 67.7, df = 1, P < 0.001; Table 1). If we expected a uni- form temporal distribution, each of the months of Feb- ruary, October, and November had significantly more re- cords than the other months combined (all x^ > ^-5, df = 1, P < 0.01). Conversely, each of the months May- August have significantly fewer records than the other months combined (all x^ > 4.2, df = 1, P < 0.05). More than 40% of the records refer to the Osprey (Pandion haliaetus). The three least common species (Swallow-tailed Kite \Elanoides forficatus] , Yellow-headed Caracara [Milvago chimachima] , and American Kestrel [Falco sparverius] ) make up only 4% of the total sample The Osprey was the only nonbreeding raptor recorded 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- ber of these migrants may have remained on the island during the boreal summer. Discussion Species Composition. We documented six species of migrant raptors on Bonaire, three of which were not in- cluded in Voous’ (1983) list of birds for the island. We documented seven records of American Kestrel from all seasons dating as far back as 1948. The species is com- mon in the region and probably was a regular visitor to Bonaire, although Voous (1957, 1983) was reluctant to accept any records of the species. Records of the other two species were more recent, the Yellow-headed Cara- cara in December 1996, and the Swallow-tailed Kite in April 2002 (Mlodinow 2004). The former occurs throughout northern South America (Ferguson-Lees and Christie 2001). In the Netherlands Antilles it previously has been recorded on Curasao only (January 1952; Voous 1983). The Swallow-tailed Kite has a disjunct dis- tribution and breeds in the southern United States (now mainly Florida and adjacent states) and from southern Mexico south to Argentina (Ferguson-Lees and Christie 2001). Kites from northern and central America migrate southwards during the boreal winter, whereas little is known about movements of populations in northern South America. Recentiy, the species was recorded on Aruba (March 2003; Mlodinow 2004), suggesting that the sighting on Bonaire might not be as unusual as previously thought. In addition to these species, observations of a Northern Harrier {Circus cyaneus) on Curasao (October- November 1997) suggested that this northern migrant also can be expected to pass through Bonaire (B. de Boer pers. comm.). All of the migrants from Bonaire have been recorded on the other islands in the Netherlands Antilles, and one, the American Kestrel, breeds on Aruba and Curasao (Voous 1983). Two of the species, the Osprey and the Peregrine Falcon, are known from the Los Roques Is- lands east of Bonaire (Zalles and Bildstein 2000). Timing of Migrant Raptors. Several distinct phases can be recognized with respect to the timing of northern mi- grant raptors on Bonaire. The first phase from Septem- ber-November was characterized by the arrival and pas- sage of a relatively large number of migrants, presumably mostly from North America, en route to mainland South America. In December and January, the number of rec- ords was considerably lower and these, in part, likely rep- resented birds that over-winter on the island. The second, albeit smaller, peak from February-March probably com- prised birds on return migration to their breeding grounds. Finally, a small number of individuals remained on the island in boreal summer from April-August. A similar temporal pattern has been observed in migrant passerine birds in xerophytic habitats on the Paraguana Peninsula, Venezuela, 150 km west of Bonaire (Bosque and Lentino 1987), that is a conspicuous fall migration. little overwintering, but with an even less conspicuous spring migration. Most migrant raptors arriving on Bonaire breed in northern latitudes, although a small number (i.e., Yellow- headed Caracara and, most likely, Swallow-tailed Kite; Mlodinow 2004) originate from mainland South America (Venezuela, Colombia). Few data are available on move- ments of raptors in northern South America, but at least some are partly migratory (ffrench 1973; Ferguson-Lees and Christie 2001). One species, the American Kestrel is a breeding resident on Aruba and Curasao, where its main breeding season is November-February (Voous 1957, 1983). The few records we compiled from Bonaire were from throughout the year, but may well have been either first-year birds dispersing from these nearby is- lands, or alternatively, birds from northern regions. Systematic studies of raptor migration on Caribbean islands are rare, and compared to other parts of the Northern Hemisphere little is known about the species composition and timing of migrants in the region (Zalles and Bildstein 2000). Our data set was comprised of rec- ords obtained opportunistically, and includes the island of Bonaire only. Extending our analysis to other islands in the south Caribbean islands and to mainland areas m northern South America (including the Paraguana Pen- insula) may be a promising avenue along which to pro- ceed with further research. Temporada de Estancia y Abundancia de Ayes Rap aces EN Bonaire, Antillas Holandesas Resumen. — Se colectaron 202 registros de seis especies de aves rapaces de la isla de Bonaire, Antillas Holandesas, incluyendo tres especies reportadas nuevamente en la isla {Elanoides forficatus, Milvago chimachima y Falco sparv- erius). Basandonos en estos datos discutimos la tempor- ada de estancia y la abundancia de rapaces migratorias en la isla. La abundancia maxima de migrantes tiene lu- gar dos veces al aho durante febrero y marzo (20% del total anual) y durante octubre y noviembre (35%), sim- ilar al patron observado en las cercanfas de Venezuela Se identificaron tres grupos de aves rapaces migratorias. El primero, migrantes de Norte America que pasan por Bonaire hasta llegar a las planicies de Sudamerica; el se- gundo, especies que se dispersan por Sudamerica hasta llegar a Bonaire; y el tercero, residentes que se alimentan cerca de las islas y que ocasionalmente se registran en Bonaire. [Traduccion de los autores] Acknowiudgments We would like to thank the large number of observers that over the years have submitted their records, includ- ing C. Beachell, B. de Boer, M. Flikweert, G. van Hoorn, J.C. Ligon, and S. Mlodinow. Financial support was re- ceived from the Van der Hucht Fund. K.L. Bildstein, R. Yosef, and G.S. Kaltenecker commented on the manu- script. F.R. Schram assisted with editing our English, and March 2005 Short Communications 97 E. van der Vorst Roncero translated the abstract into Spanish. Literature Cited Bosque, C. and M. Lentino. 1987. The passage of North American migratory land birds through xerophitic habitats on the western coast of Venezuela. Biotrop. 19: 267-273. Ferguson-Lees, J. and D.A. Christie. 2001. Raptors of the world. Christopher Helm, London, U.K. FFRENCH, R. 1973. A guide to the birds of Trinidad and Tobago. Livingstone Publishing Company, Wynne- wood, OK U.S.A. Mlodinow, S.G, 2004. First records of Little Egret, Green-winged Teal, Swallow-tailed Kite, Tennessee Warbler, and Red-breasted Blackbird from Aruba. N. Am. Birds 57 '.BBd-B&l. Nijman, V. 2001. Spatial and temporal variation in mi- grant raptors on Java, Indonesia. Emu 101:259-263. Prins, T.G. and A.O. Debrot. 1996. First record of the Canada Warbler for Bonaire, Netherlands Antilles. Canbb.J Sci. 32:248-249. Thiollay, J.-M. 1978. Les migrations des rapaces en Af- rique occidentale: adaptations ecologiques aux fluc- tuations de production des ecosysteraes. Terre Vie 32 89-133. Voous, K.H. 1957. The birds of Aruba, Curasao, and Bo- naire. Stud. Fauna Curasao other Canbb. Isl. 29:1—260 . 1982. Straggling to islands — South American birds in the islands of Aruba, Curagao, and Bonaire, South Caribbean. J. Yamashina Inst. Ornithol. 14:171- 178. . 1983. Birds of the Netherlands Antilles. De Wal- burg Press, Utrecht, Netherlands. . 198.5. Additions to the avifauna of Aruba, Cura- sao and Bonaire, South Caribbean. Ornithol. Monogr. 36:247-254. Zatles, J.I. and K.L. Bildstein (Eds.). 2000. Raptor watch: a global directory of raptor migration sites BirdLife Conservation Series 9. BirdLife Internation- al, Cambridge, U.K. and Hawk Mountain Sanctuary, Kempton, PA U.S.A. Received 8 January 2004; accepted 3 June 2004 Associate Editor: James R. Belthoff J Raptor Res. 39(1):97-101 © 2005 The Raptor Research Foundation, Inc. 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 1 7 Essen, Germany Key Words: Barn Owl; Tyto alba; diet, Chile, feeding ecology; anthropogenic disturbance. Several studies on the diet of the Barn Owl ( Tyto alba) related to broader investigations of predator-prey rela- tionships have been conducted in Chile, most of which involved data collected in the semi-arid north-central zone of this country (e.g., Schamberger and Fulk 1974, Jaksic et al. 1992, 1993b). The majority of these studies dealt with predator-prey interactions, and little attention was paid to human influences on the Barn Owl’s diet (e.g., Schlatter et al. 1980, Simeone 1995). Indeed, most of these studies were conducted in areas of reduced hu- man activities such as the Fray Jorge National Park ^ Email: sabine.begall@uni-essen.de (Schamberger and Fulk 1974, Fulk 1976, Jaksic et al. 1993b), the Chinchilla National Reserve (Jaksic et al 1992), or the Atacama De.sert (Jaksic et al. 1999). Dis- turbances of hunting habitats by human activities such as agriculture or pollution may differentially affect the oc- currence or abundance of small mammals, and thus, the diet of the Barn Owl. In this study, I examine the diet of Barn Owls occu- pying two ecologically-dissimilar study areas. Although both sites are affected by humans, their extent of distur- bance differs. One study site (El Alamo) , located in the south of central Chile, consisted mainly of meadows and was only slightly influenced by human settlement. In con- trast, the second habitat (Los Maitenes) appeared to be noticeably polluted by the copper-processing industry as indicated by substantially reduced vegetative cover. Fur- 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, Herrera and Jaksic 1980), and thus, allows comparisons between data sets. Materials and Methods Owl pellets were collected from two localities in central Chile (El Alamo and Los Maitenes) during field studies conducted in January and March 1998. At both localities. Barn Owls were observed using the roosts from which the pellets were collected. The study site at El Alamo (36°11'S, 72°24'W) comprised mainly open vegetation (meadows grazed by cattle, goats, and sheep) with many shrubs and relatively complete vegetation cover (80— 100%) and scattered fields. The landscape was inter- spersed with forest fragments (<20%). A total of 318 pel- lets were collected in abandoned barns at six sites near settlements within an area of ca. 80 km^. At Los Maitenes (32°46'S, 7l°27'W), 239 pellets were collected in and nearby roosts that were located in the walls of a gorge, ca. 3 km from the nearest village. The five sampling sites were located within a radius of ca. 5 km. This area was contaminated by sulphur dioxide and arsenic emitted by an adjacent copper-processing refin- ery (J. Bustamente, Empresa Nacional de Minera Ven- tanas, pers. comm.) ca. 6 km from the sampling site. The vegetation was poorly developed with only a few shrubs, a reduced vegetative ground cover (<20%), and the soil did not contain geophytes (Begall and Gallardo 2000). The land has not been used for agriculture for at least two decades. I dissected pellets after soaking them in water, and mammalian skulls were identified using the key by Reise (1973). In the case of uncertainty, skulls (especially teeth) were compared with specifications and drawings by Osgood (1943) and for cricetine rodents with an on- line key (Huiha-pukios Limitada 2002). Scientific nomen- clature followed Jaksic (1997) for vertebrates. Prey per pellet was estimated by summing up the num- bers of identified individual prey animals divided by the total number of pellets analyzed. Calculations of the min- imum number of specimens per pellet were derived from the maximum number of either left or right elements of cranial and postcranial bones (Lyman et al. 2003). Diet breadth (Bq^s) was calculated using the term (Ef=i with pj being the fraction of prey category i (Levins 1968). This index can yield values ranging be- tween 1-3 (according to N = three prey categories: mam- mals, birds, and insects). In addition, 1 calculated stan- dard niche breadths according to the equation B,, = (B„bs - Bmin)/(Bn,ax ~ B^;„) (Colwcll and Futuyma 1971). Geometric mean weight of prey (GMWP) was cal- culated using the formula GMWP = antilog pi log TO,) where p, is defined as above and W; is the mass of prey category i. Data on body mass of mammalian prey were obtained 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. Means are given as x ± SD (standard deviation), and mean prey sizes were com- pared using Kest. Resuits Altogether 689 individual prey were identified from skulls found in 557 owl pellets, resulting in 1.24 prey per pellet. However, estimates of the minimal number of specimens based on cranial and postcranial bones ac- counted for 1.81 animals per pellet. The Barn Owl fed mainly on mammals (98.1%), or more precisely on ro- dents (96.4%); the remaining 3.6% consisted of marsu- pials (1.15%), lagomorphs (0.6%), birds (1.15%), and insects (0.7%). A total of 12 mammal species was iden- tified, of which 10 were rodents (Table 1). Furthermore, remains of eight birds, and elytra and chitin shells of five beetles (Coleoptera) were found in the prey. Diet breadths calculated for the broad prey categories mam- mals, birds, and insects were comparable for both study sites (Bobs = 1.04 for El Alamo and Los Maite- nes, respectively), and thus, yielded low standard niche breadths (B^f = 0.026 and 0.021 for El Alamo and Los Maitenes, respectively) . Mammalian prey composition differed between the two localities (Table 1). Differences in the consumed prey across the respective rodent families were significant (X^-test; P < 0.001). Whereas the cricetine rodents {Au- liscomys micropus, Oligoryzomys longicaudatus, and Phyllotis darwini) were more abundant in the owl’s diet from Los Maitenes than in pellets originating from El Alamo, the reverse was true for Abrothrix longipilis (Table 1). Because the body mass of the respective species ranged between 30-70 g, the distribution of prey according to body mass (Fig. 1) shows a slightly higher amount of medium-sized prey (<70 g) for Los Maitenes. Barn Owls from El Alamo seemed to take heavier prey like Rattus rattus or Octodon bridgesi, with the latter being absent in Los Maitenes. The fossorial coruro {Spalacopus cyanus) was found more of- ten in pellets from Los Maitenes (7.8%) than in the southern locality El Alamo (2.0%). The differences of mammalian prey composition in the diet of the Barn Owl resulted in significantly lower GMWP at Los Maitenes (54.4 ± 25.3 g) in comparison to El Alamo (66.1 ± 36.4, P< 0.001). Discussion One of the sampling localities (Los Maitenes) lies with- in the geographical range of sampling localities of two previous studies addressing the diet of the Barn Owl m central Chile (Jaksic and Yanez 1979, Herrera and Jaksic 1980). In these studies, a slightly different Barn Owl prey spectrum was found compared to the present findings Nevertheless, both this study and the previous ones re- vealed that the most important prey (>50%) consisted of Phyllotis darwini and Oligoryzomys longicaudatus. While Herrera and Jaksic (1980) found Al/rocoma bennetti and Octodon degus in the diet of Chilean Barn Owls with pro- portions of 4% and 3%, respectively, these rather large octodontoids (body mass of adults > 200 g) were absent in pellets that I had analyzed. Also chiropteran skulls, 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. Species Body Mass ( g) El Alamo N{7o) Los Maitenes 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 or Los Maitenes, a difference which may be related to a larger sample size in the earlier study. On the other hand, the cricetid rodent Auliscomys micropus was present at Los Maitenes (5.4%) as well as at El Alamo (0.6%), yet absent in previous studies (Jaksic and Yanez 1979, Her- rera and Jaksic 1980). The differences between prey compositions found at El Alamo and Los Maitenes may be due to differences in 90 > 80 £ Q. 70 I 60 t 50 0 ® 40 O) 1 30 0 ) o 20 0) 0 - 10 0 Figure 1. Percentage of prey in body mass taken by Barn Owls from two localities from central Chile (white bars represent samples from Los Maitenes, black bars samples from El Alamo) . Data on body mass were taken from Begall et al. (1999) for Spalacopus cyanus, from Bed- ford and Eisenberg (1992) for Auliscomys micropus and Octodon sp., and from Herrera and Jaksic (1980) for the remaining taxa. < 30 g 30 - 69 g 70 - 1 00 g > 1 00 g Body Mass Classes prey availability. However, I did not assess availability of prey by trapping except for Spalacopus cyanus (Begall and Gallardo 2000; see below). Nevertheless, different fre- quencies of Oligoryzomys longicaudatus, Phyllotis darwim, and Abrothrix olivaceus found in the pellets from the two study sites may be related to prey availability. Bodent out- breaks in the above mentioned species occur at regular intervals and may depend on bamboo flowering, rainfall peaks, but also on density-dependent factors (Gallardo and Mercado 1999, Lima and Jaksic 1999, Jaksic and Lima 2003). Other striking differences between the two sampling localities were found with Octodon bridgesi (El Alamo' 17.0%; Los Maitenes: 0%) and Abrothrix longipilis (11.0% versus 0.6%). While Octodon bridgesi is absent at Los Mai- tenes (and the surrounding area), Abrothrix longipilis is most common in moister areas (like El Alamo) with a high proportion of shrub and litter cover (Bedford and Eisenberg 1992) — conditions that are absent at Los Mai- tenes. Furthermore, Abrothrix longipilis was also reported to exhibit cyclic populations (Murua et al. 2003) that may have contributed to differing frequencies of this species between the study sites. Higher amounts of Rattus rattus remains in pellets from El Alamo (9.6% versus 0.9%) cer- tainly indicated the close association of the rat with hu- mans. Skulls of Spalacopus cyanus in pellets analyzed by Her- rera and Jaksic (1980) accounted for 0.8% of the Barn Owl diet even a smaller fraction than at El Alamo (2%) during the current study. In contrast to these findings, Spalacopus cyanus accounted for 7.8% of the Barn Owl 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 five colonies of Spalacopus cyanus were found in imme- diate vicinity (<2 km) of sampled roosts. Furthermore, mean colony sizes were similar at both localities (Begall et al. 1999, Begall and Gallardo 2000) suggesting similar population densities. Perhaps low vegetation cover and absence of geophytes at Los Maitenes force Spalacopus to forage above ground (on leaves of Convolvulus arvensis) more frequently, and thus, exposing them to greater pre- dation pressure. In contrast, at El Alamo Spalacopus cy- anus spent most time underground foraging on bulbs of the geophyte Dioscorea longipes (Begall and Gallardo 2000) . Despite the absent underground-food resource at Los Maitenes, Spalacopus cyanus maintains its typical com- plex burrow network presumably to avoid even higher levels of predation. Although there were several noticeable differences be- tween the two foraging habitats. Barn Owls seemed to be equally abundant in both areas and exploited a similar mammalian-prey-based diet with comparable diet breadths. This finding indicated that sufficient mamma- lian prey was also available at the disturbed area of Los Maitenes for Barn Owls and corroborates that this species specializes on mammalian prey. Long-term studies byjak- sic et al. (1992, 1993a) revealed that if mammalian prey decreases. Barn Owls tend to abandon the area rather than shift toward non-mammalian prey as seen in some other predator species (e.g., Bednarz and Dinsmore 1985, Selas 2001). The results of this study showed that Chilean Barn Owls took prey of medium body mass. Even the mean value calculated for the study site at Los Maitenes (GMWP = 54.4 g) was almost twice as high as the value calculated for prey of Barn Owls from Chilean Patagonia (Iriarte et al. 1990). Higher abundances of large animals like Rattus rattus and Octodon bridgesi at El Alamo may have led to significantly higher mean prey mass at this locality (GMWP = 66.1 g). Studies of White-tailed Kites {Elanus leucurus) in central Chile revealed a similar pat- tern (Schlatter et al. 1980). They found that prey taken in the undisturbed babitat was significantly heavier than prey taken at the disturbed area. Schlatter and colleages related the higher proposed that kites from anthropo- genically-disturbed areas may have had access to more prey due to greater prey abundance or higher prey vul- nerability. Whereas, I suggest there was not higher prey abundance in Los Maitenes due to lower habitat quality. Rather, I assume that higher prey vulnerability at Los Maitenes may be supporting the current Barn Owl pop- ulation. ECOLOGIA DE ALIMENTACION DE TYTO alba EN el CENTRO DE Chile y su Relacion con el Habitat de Caza Resumen. — Se comparo la composicion de la dieta de Tyto alba en dos localidades de la region central de Chile (El Alamo y Los Maitenes), relacionandose posterior- mente los resultados obtenidos con las caracteristicas de ambos habitats. La region de El Alamo consistio princi- palmente en campos cultivados y prados, mientras que la region de Los Maitenes se caracterizo por presentar una cubierta vegetal escasa, encontrandose fuertemente afec- tada por la polucion generada por la presencia de in- dustrias de cobre en las cercanias. En ambas areas de estudio, T. alba mostro una amplitud de dieta estrecha, representando los mamiferos un 98% del total de presas. Sin embargo, la composicion de la dieta vario marcada- mente entre los dos sitios de estudio, encontrandose una mayor frecuencia de roedores fosoriales de gran tamano en areas alteradas que en aquellas areas que presentaban una cubierta vegetal densa. Finalmente, los tamanos de las presas en la regi6n de Los Maitenes fueron menores que los obtenidos en la region de El Alamo. [Traduccion de los autores] Acknowiedgments I thank Julio Montes who helped collect pellets. Fredy Mondaca (Universidad Austral de Chile, Valdivia) helped in identifying skulls of Chilean small mammals. I greatly appreciated help by Oliver Erdmann and Julia Baron (University of Duisburg-Essen) for laboratory assistance, and Hynek Burda, Ana Trejo, and two anonymous re- viewers for comments on the manuscript. Literature Cited Bednarz, J.C. and J.J. Dinsmore. 1985. Flexible dietary response and feeding ecology of the Red-shouldered Hawk, Buteo lineatus, in Iowa. Can. Field-Nat. 99:262- 264. Begall, S. and M.H. Gallardo. 2000. Spalacopus cyanus (Octodontidae, Rodentia): an extremist in tunnel constructing and food storing among subterranean mammals./. Zool. (Lond.) 251:53-60. , H. Burda, and M.H. Gallardo. 1999. Reproduc- tion, postnatal development, and growth of social co- ruros, Spalacopus cyanus (Octodontidae, Rodentia) from Chile./. Mammal. 80:210-217. Colwell, R.K. and D.J. Futuyma. 1971. On the measure- ment of niche breadth and overlap. Ecology 52:567- 576. Fulk, G.W. 1976. Owl predation and rodent mortality a case study. Mammalia 40:423—427. Gallardo, M.H. and C.L. Mercado. 1999. Mast seeding of bamboo shrubs and mouse outbreaks in southern Chile./. Neotrop. Mammal. 6:103-111. Herrera, C.M. and F.M. Jaksic. 1980. Feeding ecology of the Barn Owl in central Chile and southern Spain, a comparative study. Auk 97:760-767. Huina-pukios Limitada. 2002. Clave de indentificacion anatomica oseo-craneal para generos de cricetidos www.geocities.com/biodiversidadchile/cricetch.htm Iriarte, J.A., W.L. Franklin, and W.E. Johnson. 1990. Diets of sympatric raptors in southern Chile./. Raptor Res. 24:41-46. March 2005 Short Communications 101 Jaksic, F.M. 1997. Ecologia de los vertebrados de Chile. Ediciones Univ. Catolica de Chile, Santiago, Chile. AND M. Lima. 2003. Myths and facts on ratadas: bamboo blooms, rainfall peaks and rodent outbreaks in South America. Aust. Ecol. 28:237-251. AND J.L. YAnez. 1979. The diet of the Barn Owl in central Chile and its relation to the availability of prey. Auk 96:619—621. , J.E. Jimenez, S.A. Castro, and P. Feinsinger. 1992. Numerical and functional response of predators to a long-term decline in mammalian prey at a semi- arid Neotropical site. Oecologia 89:90-101. , P. Feinsinger, and J.E. Jimenez. 1993a. A long- term study on the dynamics of guild structure among predatory vertebrates at a semi-arid Neotropical site. Oikos 67:87-96. , P.L. Meserve, J.R. Gutierrez, and E.L. Tabilo. 1993b. The components of predation on small mam- mals in semiarid Chile: preliminary results. Rev. Chil. Hist. Nat. 66:305-321. , J.C. Torres-Mura, C. Cornelius, and P.A. Mar- QUET. 1999. Small mammals of the Atacama Desert (Chile), y. Arid Environ. 42:129-135. Levins, R. 1968. Evolution in changing environments: some theoretical explorations. Princeton Univ. Press, Princeton, NJ U.S.A. Lima, M. and F.M. Jaksic. 1999. Population dynamics of three Neotropical small mammals: time series models and the role of delayed density-dependence in pop- ulation irruptions. Aust. J. Ecol. 24:25-34. Lyman, R.L., E. Power, and RJ. Lyman. 2003. Quantifi- cation and sampling of faunal remains in owl pellets J. Taphonomy 1: 3-14. Murua, R., L.A. Gonzalez, and M, Lima. 2003. Second- order feedback and climatic effects determine the dy- namics of a small rodent population in a temperate forest of South America. Popul. Ecol. 45:19-24. Osgood, W.Ff. 1943. The mammals of Chile. Field Mu- seum of Natural History, Chicago, IL U.S.A. Redford, K,H. and J.F. Eisenberg. 1992. Mammals of the Neotropics: the southern cone. Vol. 2. Univ. Chicago Press, Chicago, IL U.S.A. Reise, D. 1973. Clave para la determinacion de los cra- neos de marsupiales y roedores chilenos. Guyana {Tool.) 27:1-20. Schamberger, M. and G. Fulk. 1974. Mamiferos del parque nacional Fray Jorge. Idesia 3:166-179. Schlatter, R.P., B. Toro, J.L. YAnez, and F.M. Jaksic 1980. Prey of the White-tailed Kite in central Chile and its relation to the hunting habitat. Auk 97:186- 190. Selas, V. 2001. Predation on reptiles and birds by the Common Buzzard, Buteo buteo, in relation to changes in its main prey, voles. Can. J. Zool. 79:2086-2093. SiMEONE, A.C. 1995. Ecologia trofica del bailarin Elanus leucurus y la lechuza Tyto alba y su relacion con la in- tervencion humana en el sur de Chile. Tesis de licen- ciatura, Univ. Austral de Chile, Valdivia, Chile. Received 11 February 2004; accepted 21 November 2004 Letters J Raptor Res. 39(1):102-103 © 2005 The Raptor Research Foundation, Inc. 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 the Mt. Baker-Snoqualmie National Forest, Washington (Iverson 2004, J. Raptor Res. 38:88-91). He compared repro- duction 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 occiden- talis) 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 detec- tion 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 repro- duction. 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: kentJivezey@fws.gov), 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 J Raptor Res. 39(1):103-106 © 2005 The Raptor Research Foundation, Inc. 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 sub- sequent 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: techubbs@cablelab.net), 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 J Raptor Res. 39(1): 106-107 © 2005 The Raptor Research Foundation, Inc. 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, partic- ularly 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 fre- quently 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 manu- script. — James A. Fitzsimons (e-mail address: fitzsimo@deakin.edu.au). 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 /, Raptor Res. 39 ( 1 ) : 1 08 © 2005 The Raptor Research Foundation, Inc. Red-tailed Hawk Depredates Mississippi Kite Nestling at Dawn Nesting ecology and demographics of the Mississippi Kite {Ictinia mississippiensis) remain unstudied in the south- eastern 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: karl.miUer@MyFWC.com), 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 J Raptor Res. 39(1): 109 © 2005 The Raptor Research Foundation, Inc. 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: rdcny@earthlink.net), 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 J Raptor Res. 39 ( 1 ) : 1 1 0 © 2005 The Raptor Research Foundation, Inc. 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*, D. Ellis*, S. England, D. Evans, C. Farquhar, M. Ferrer, J. Figuerola, L. Flake, G. Foster, P. 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 Books Toll Free: 800-722-2460 phone: 434-263-8671 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 of out-of-print titles available. A FEW BOOKS ON BIRDS OF PREY AND FALCONRY Raptors of Eastern North America. Brian Wheeler. 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. 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Try the New R-2000 and YouV Be Impressed! COMMUNICATIONS SPECIALISTS, INC. 426 West Taft Avenue • Orange. CA 92865-4296 • 1-714-998-3021 • Fax 1-714-974-3420 Entire U.S.A. (800) 854 0547 • Fax (800) 850-0547 • http;//www.com spec.com 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. The Journal of Raptor 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 The Journal 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: cboal@ttu.edu 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: pah@spruce.for.nau.edu 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: rgerhardt@madras.net 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 sup- port research and conservation of raptors, especially to students and amateurs with limited access to alter- native 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: cgriff@liu.edu 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: JeffLincer@tns.net