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Eagles, Hawks and Falcons of the World

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... The nape patch is often gleaming golden in color and the feathers here are exceptionally long Gavrilov, and Gavrilov, (2005). Ferguson-Lees, and Christie, (2001), Brown, and Amadon, (1986). ...
... Up to 20 species have been categorized in the genus, however more recently the taxonomic placement of some of the traditional species has been questioned. Habitually, the Aquila eagles have been grouped superficially as largish, mostly brownish or dark-colored booted eagles that vary little in transition from their juvenile to their adult plumage Brown, and Amadon (1986). as shown in Figure No (89). ...
... Golden eagles usually hunt during daytime hours, whereas, were documented hunting from one hour previously sunup to one hour after sundown through the breeding season in southwestern Idaho. A mature golden eagle necessitates about 230 to 250 g of food per day whereas, in the life of most eagles there are cycles of feast and scarcity, and eagles have been identified to go deprived of food for up to a week and then gorge on up to 900 g at one sitting Brown, and Amadon, (1986). ...
... According to Brown (1967), hens often nest within one-half mile of the breeding ground, and they have brood ranges of 0.6 to 1.25 miles from the ground for up to eight weeks of brood development. ...
... At most times it is likely to be aggressive toward other birds of prey. It commonly kills birds wounded by human hunters (Brown and Amadon 1968). ...
... This is the first record of the Ancient Murrelet, or any member of the family Alcidae, for Alberta. Scattered reports describe close nest associations of passerines and raptors (Robson 1955;Rotschild 1959;Brown and Amadon 1968;Garber 1972). Bent (1937) noted that small birds, typically the Western Kingbird (Tyrannus verticalis) and Northern Oriole (Icterus galbula), will occasionally nest near a Swainson's Hawk (Buteo swainsoni) nest. ...
... The landowner informed me that a pair of Swainson's Hawks used the same location in 1976, confirming the existence of a nest structure throughout the period of sparrow nest-site selection. Brown and Amadon (1968) consider doubtful the possibility that benefit accrues to weaverbirds of the genera Malimbus and Ploceus that nest near raptors. This places my observations in an interesting context. ...
... The nest was on the north west face of a 20 m high cliff, 2 m from the top. On 31 July, the nest contained five young, which were approximately 12 days old, judging from the amount of gray and white down on each chick, with the two largest nestlings showing some wing feathers (Brown and Amadon 1968;Harrison 1978). ...
... Data in this study on feeding behaviour in nesting Rough-legged Hawks differ from some previous reports. Female Rough-legged Hawks have been reported as not hunting at all for food for the young (Brown and Amadon 1968), or as remaining close to the nest and not hunting until the young are wellfeathered (Harrison 1978). Not only did the female contribute substantially to the feeding of the nestlings but she left the nest and hunted for prey while the young were still covered in down. ...
... The percentage of the 43 alive at the end of each calendar year was calculated using the total number of different individuals seen after 31 December of that year. For analysis of survival of banded birds we used the method of Brown and Amadon (1968) to calculate survival, except that instead of presenting data in terms of percent mortality, we used percent survival. Thus, a 79% mortality of birds in their first year (data from Brown and Amadon 1968) is listed as a 21% survival in Table 1. ...
... Owing to the small numbers of birds involved in both these samples, with resulting wide confidence intervals, and owing to the fact that both estimates must be considered minimal, there is no significant difference in the two results. Both survival rates (Brown and Amadon 1968) 21(23/ 107) 13-31 9(10/ 107) 4-17 4(4/ 107) 1-10 *Includes one marked bird found dead which had lost its markers but retained its band. **Significantly different from previously published data (P < 0.05). ...
... Collared Forest-Falcons, Crane Hawks, Gray Hawks, and Roadside Hawks are four of the most abundant resident raptor species in the tropical dry forest along the coast of Jalisco (Martínez-Ruiz et al. 2020). These four focal species include a range of body size and varying ecological requirements (Brown and Amadon 1968, Johnsgard 1990, Panasci 2012, Sutter 2012, Thorstrom 2012, Bibles et al. 2020. Collared Forest-Falcons (560-940 g) and Crane Hawks (495 g) are medium-sized raptors (Brown and Amadon 1968) of the forest interior (Thorstrom 2000, Sutter et al. 2001, Thorstrom 2012. ...
... These four focal species include a range of body size and varying ecological requirements (Brown and Amadon 1968, Johnsgard 1990, Panasci 2012, Sutter 2012, Thorstrom 2012, Bibles et al. 2020. Collared Forest-Falcons (560-940 g) and Crane Hawks (495 g) are medium-sized raptors (Brown and Amadon 1968) of the forest interior (Thorstrom 2000, Sutter et al. 2001, Thorstrom 2012. Collared Forest Falcons nest in tree cavities and hunt from a perch in dense vegetation (Thorstrom 2012), while Crane Hawks build nests in the forest canopy and employ a distinctive search-andprobe hunting technique seeking prey in tree hollows, epiphytes, and behind bark (Sutton 1954, Jehl 1968, Sutter et al. 2001. ...
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Little is known of intra- and inter-specific territoriality in Neotropi- cal raptors that may defend territories throughout the year, and face greater inter-specific competition for resources. We evaluated intra- and inter-specific territorial responses of four species of Neotropi- cal raptors in the tropical dry forest of the Chamela-Cuixmala Bio- sphere Reserve, Mexico. We conducted broadcast calls in territories of the Collared Forest-Falcon (Micrastur semitorquatus), Crane Hawk (Geranospiza caerulescens), Gray Hawk (Buteo plagiatus), and Roadside Hawk (Rupornis magnirostris), and measured the la- tency, duration, and type of territorial response to broadcast calls of conspecifics and sympatric raptor species. We applied repeated measures analysis to determine differences in intra- and inter-specif- ic territorial responses of raptors, and GLMMs to evaluate whether traits of body size, nest type, and hunting technique were associated with territorial response by focal raptors. Large-bodied focal raptor species showed high intra-specific territoriality, giving faster, pro- longed responses of various types, including duets and combined responses, to broadcast calls of conspecifics compared to sympat- ric species. All focal raptors showed some inter-specific territori- al response, but this was mainly as vocalizations or displacements towards sympatric species broadcast calls. Species traits of body size, nest type, and hunting technique were associated with latency and duration of territorial response by the larger raptor species that nest in the forest canopy. These traits may be more strongly asso- ciated with territorial response of forest raptors that defend limited resources in a structurally complex environment.
... El águila mora tiene una amplia distribución en Sudamérica, encontrándose desde Colombia hasta Tierra del Fuego, por ambos lados de la Cordillera de los Andes (Goodall et al., 1951;Brown y Amadon, 1968). Por la vertiente oriental de los Andes se extiende desde el sur de Brasil hasta el sur de Argentina (Goodall et al., 1951;Brown y Amadon, 1968). ...
... El águila mora tiene una amplia distribución en Sudamérica, encontrándose desde Colombia hasta Tierra del Fuego, por ambos lados de la Cordillera de los Andes (Goodall et al., 1951;Brown y Amadon, 1968). Por la vertiente oriental de los Andes se extiende desde el sur de Brasil hasta el sur de Argentina (Goodall et al., 1951;Brown y Amadon, 1968). Por sus hábitos y tamaño -1670 a 3170 gramos-(Jiménez y Jaksic, 1990) esta rapaz es una de las más conspicuas de América del Sur (Jiménez y Jaksic, 1990). ...
... Esta especie habita diversos ambientes acuáticos del norte y este de la provincia de Buenos Aires (Narosky y Di Giacomo, 1993). Su presencia está condicionada prinapalmente a la disponibilidad de caracoles del género Pomacea, de los cuales se alimenta casi con exclusividad (Brown y Amadon, 1968 Queda aún por evaluar si la ecpeeie se reproduce en el área, lo cual podna darse a juzgar por las caractehlicm del hábitat. Asimismo, debido a la introducción exitosa de Pomacea canaliculata en el dique Paso de las Piedras (38"26'43,4"S, 61°39'54,9"W), partido de Coronel Fringles, fue observado un individuo (fecha sinpreasar). ...
... La especie se distribuye desde la ~f o -: , , rida en los Estados Unidos hasta el norte y centro de la Argentina. Está considerada como una especie " altamente especializada en la captura de caracoles acuáticos y su rango de distribución en la Argenti-" na se encuentra correlacionado con la presencia de caracoles del género Pomacea (=Ampullaria) de los cuales se alimenta casi con exclusividad (Brown y Amadon, 1968;Del Hoyo ef al., 1994). En la Argentina habita la forma R. s. sociabilis, la cual se distribuye desde las provincias de Jujuy, Salta, Tucumán, Catamarca y Córdoba hasta el centro de Buenos Aires (Narosky e Yzurieta, 1987; Canevari ef ni., i 1991). ...
... Our understanding of the trophic ecology of Atacama Desert raptors has increased in recent years, particularly for the variable hawk Geranoaetus polyosoma and the barn owl Tyto furcata. Geranoaetus polyosoma is a species of raptor of the Accipitridae family, which has a wide distribution in South America; it has a northern distribution from the central mountain range of Colombia to Cabo de Hornos in the south, and from the coasts of Chile to Argentina (Brown and Amadon 1968;Cabot 1991;De Lucca 2011), reaching the Malvinas Islands in the Atlantic (Cabot 1991) and the Juan Fernández Islands in the Pacific (Blake 1977). It is considered one of the most studied raptors in Chile (Raimilla et al. 2012); it is sexually dimorphic (Brown and Amadon 1968), of medium size, with a wingspan of 1100 mm, body length between 450 and 530 mm for males and 485 and 630 mm for females, but adult males between 690 and 1134 g and adult females between 876 and 1417 g (Jiménez 1995). ...
... Geranoaetus polyosoma is a species of raptor of the Accipitridae family, which has a wide distribution in South America; it has a northern distribution from the central mountain range of Colombia to Cabo de Hornos in the south, and from the coasts of Chile to Argentina (Brown and Amadon 1968;Cabot 1991;De Lucca 2011), reaching the Malvinas Islands in the Atlantic (Cabot 1991) and the Juan Fernández Islands in the Pacific (Blake 1977). It is considered one of the most studied raptors in Chile (Raimilla et al. 2012); it is sexually dimorphic (Brown and Amadon 1968), of medium size, with a wingspan of 1100 mm, body length between 450 and 530 mm for males and 485 and 630 mm for females, but adult males between 690 and 1134 g and adult females between 876 and 1417 g (Jiménez 1995). The diet of variable hawk in Chile was first studied by Schlatter et al. (1980) and Jiménez (1995). ...
Article
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The diets of the variable hawk (Geranoaetus polyosoma) and the barn owl (Tyto furcata) have been previously reported for the Atacama Desert of northern Chile. However, their ecological interactions and their role in the control of invasive species are unknown. In this work, the diet and competitive interaction of both raptors in an agricultural landscape were evaluated. Both species consume a high proportion of rodents (26.3% and 63.3% respectively), particularly Rattus sp. (20.8% and 30.0% respectively), which represent the highest contribution to the biomass consumed (67.9% and 60.2% respectively). Geranoae-tus polyosoma consumes reptiles such as Microlophus yanezi (11.7%) and invertebrates (42.7%), mainly Coleoptera (30.7%) and Decapoda (7.11%). On the other hand, Tyto furcata consumed native rodents as Oligoryzomys flavescens (7.13%) and Auliscomys boliviensis (6.22%) and marine birds nesting in the desert, as Oceanodroma markhami (0.55%). Both raptors hunt over wide geographic ranges from the coast to the highlands, in wetlands, agricultural and desert areas. Despite sharing 44% of the prey consumed, there is only moderate interspecific competition. We discuss the possible role of both raptors as controllers of the exotic invasive Rattus sp.
... It is made sampling is needed to be confident about this result. Three members of the "true" Gypaetinae were 419 represented in our analysis by six or more legacy genes, but we lacked UCE data for this group and 420 therefore hesitate to recognize a monotypic subfamily for P. typus (Polyboroidinae) at this time, as some 421 authors have done (e.g., Brown & Amadon, 1968). Nevertheless, we acknowledge that these three 422 monotypic genera are highly divergent from each other, morphologically and ecologically (e.g., van included Aviceda species. ...
... These discrepancies are not surprising, as each study used different calibration methods. 410 GYPAETINAE, PERNINAE, & POLYBOROIDINAE 411Within the clade containing most species typically placed in the subfamilies Gypaetinae, 412Perninae, and Polyboroidinae (e.g.,Brown & Amadon, 1968; Lerner & Mindell, 2005), we found that 413 ...
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Hawks, eagles, and their relatives (Accipitriformes: Accipitridae) are a diverse and charismatic clade of modern birds, with many members that are instantly recognized by the general public. However, surprisingly little is known about the relationships among genera within Accipitridae, and several studies have suggested that some genera (in particular, the megadiverse genus Accipiter ) are not monophyletic. Here, we combine a new large dataset obtained from Ultraconserved Elements (UCEs), generated from whole genome sequencing (WGS) of 120 species, with publicly available legacy markers (i.e., a suite of commonly sequenced mitochondrial and nuclear genes) to infer a well-supported, time-calibrated phylogeny of 236 extant or recently extinct species. Our densely-sampled phylogeny, which includes 90% of recognized species, confirms the non-monophyly of Accipiter and provides a sufficient basis to revise the genus-level taxonomy, such that all genera in Accipitridae represent monophyletic groups.
... The diet of Merlin falcons has been previously stated to comprise 80% birds, and the remaining small proportion is insects (15%) and small-sized mammals (5%) (Brown and Amadon, 1968;Bibby, 1987;Sodhi and Oliphant, 1993;BirdLife International, 2023). Merlin falcons are opportunistic hunters and usually hunt an area's most abundant and available prey species (Clarke and Scott, 1994;Heavisides et al., 1995;Petty et al., 1995;McElheron, 2005;Rae, 2010). ...
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The Merlin Falco columbarius, is a small falcon widely distributed across Europe, Asia, and North America. Merlin falcons are winter visitors to north India. They occur from an arid area in Gujarat to far northeast Arunachal Pradesh. Here, we present details of the Merlin's diet on winter foraging grounds in Gujarat and Rajasthan, Western India, based on a combination of direct observations from 2009 to 2023 and secondary data extracted from various social media platforms. A total of 99 hunting events of Merlin with their prey bird were collected from the study areas, including 39 generated from direct observation of falcon hunting and 60 images of falcons with prey items acquired from various electronic media. The higher number (72) of falcon hunting events were noted from Gujarat, while a lower number (27) of observations were noted from Rajasthan. Of the total of 99 hunting events, 83 were carried out by males, 11 by females, and 5 juvenile falcons observed hunting. The hunting times of the falcons were noted in the morning (67%), in the evening (28%), and the least (5%) were recorded in midday periods. Merlins hunted and consumed 17 different types of smaller birds belonging to seven families; the highest number (45.45%) of prey items were the Greater Short-toed Lark, Calandrella brachydactyla, from Family Alaudidae and the second highest prey species (7%) was the Barn Swallow, Hirundo rustica, Family Hirundinidae. Most of the prey birds were larks of different species (70.70%), with the remaining prey birds in very low numbers. However, the present study supports an earlier study stating that a higher portion of smaller migratory birds are in the diets of Merlin falcons.
... The White-headed Vulture is sexually dimorphic in colour, a unique characteristic among the l5 Old World Vulture species (Mundy 1985, Brown & Amadon 1968) and the feature is clearly illustrated in Figure 1 (PJ Mundy pers comm). Figure 1 illustrates the adult male and female White-headed Vulture in flight in the same frame. ...
... We reviewed the descriptions and illustrations of all these subspecies in the relevant literature, including regional handbooks and guides (Dementiev & Gladkov, 1951;Cramp & Simmons,1980;Glutz von Blotzheim et al., 1989;Robson, 2000;Rasmussen & Anderson, 2005;Brazil, 2009;Del Hoyo & Collar, 2014) as well as raptor monographs (Brown & Amadon, 1968, Clark & Schmitt, 1999Ferguson-Lees & Christie, 2001;Forsman, 2016;Clark & Davies 2018), and specific books (Morozov et al., 2013;Sale, 2015). The biometric measurements used in comparisons and presented in Tab. 1 are also drawn from this literature. ...
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A Merlin (Falco columbarius) specimen collected in Pie-monte (NW Italy) in the winter of 1952 and preserved in the "Admetos Rolando Barberis" collection is here attributed to F. c. insignis, a sub-species breeding in northeastern Siberia, east of the Yenisey River. This form is reported for the first time in Italy and Europe.
... Bald eagles are North American raptors that range from Alaska to Mexico and span the continent from the Pacific to the Atlantic coast (Brown & Amadon, 1968). The Arizona population is presumed demographically closed (Allison et al., 2008) and is managed separately from the rest of the conterminous United States (Zimmerman et al., 2022). ...
Article
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Evaluating population responses to management is a crucial component of successful conservation programs. Models predicting population growth under different management scenarios can provide key insights into the efficacy of specific management actions both in reversing population decline and in maintaining recovered populations. Bald eagle (Haliaeetus leucocephalus) conservation in the United States has seen many successes over the last 50 years, yet the extent to which the bald eagle population has recovered in Arizona, an important population within the Southwest region, remains an area of debate. Estimates of the species' population trend and an evaluation of ongoing nest‐level management practices are needed to inform management decisions. We developed a Bayesian integrated population model (IPM) and population viability analysis (PVA) using a 36‐year dataset to assess Arizona bald eagle population dynamics and their underlying demographic rates under current and possible future management practices. We estimated that the population grew from 77 females in 1993 to 180 females in 2022, an average yearly increase of 3%. Breeding sites that had trained personnel (i.e., nestwatchers) stationed at active nests to mitigate human disturbance had a 28% higher reproductive output than nests without this protection. Uncertainty around population trends was high, but scenarios that continued the nestwatcher program were less likely to predict abundance declines than scenarios without nestwatchers. Here, the IPM‐PVA framework provides a useful tool both for estimating the effectiveness of past management actions and for exploring the management needs of a delisted population, highlighting that continued management action may be necessary to maintain population viability even after meeting certain recovery criteria.
... Among the wild birds, the Harpy Eagle (Harpia harpyja) is one of the world's largest raptors, with a decreasing population in the South America (Brown and Amadon, 1968). The existence of this bird species is threatened by the anthropogenic activities and illegal hunting (Giraldo-Amaya et al., 2021;Birdlife International, 2021). ...
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The eyeworms of the subgenus Thelaziella infect orbital cavities, conjunctival sacs and lachrymal ducts of many wild birds, being able to cause conjunctivitis. In Brazil, at least 10 species of Thelaziella have been described. Here we present a brief review of cases of Thelazia (Thelaziella) aquilina and describe the infection of this parasite in Harpia harpyja, as a new host record. Two nematodes were collected from the surface of the cornea of an adult female H. harpyja in the Amazon region (Brazil) and were morphologically identified as two males of T. (T.) aquilina. This data demonstrated the need for further studies focused on elucidating the transmission, biological cycle, and phylogenetic positioning of Thelaziella as subgenus.
... The function of the tomial tooth is debated for falcons of the genus Falco. Previous studies based on observations suggest the tomial tooth is used to kill prey by severing cervical vertebrae (Brown andAmadon 1968, Cade andDigby 1982). Another study indirectly supported this function for the tomial tooth; bite forces in falcons were greater than for hawks in the genus Accipiter, which are known for killing with their talons (Sustaita and Hertel 2010). ...
Article
Feeding morphology permits animals to adapt to changing environments and is often under strong selection. We evaluated if bill shape varies according to differences in dietary prey taken across geographical ranges (North America, Central America, South America, and Caribbean islands) in a ubiquitous, New World raptor species, the American kestrel (Falco sparverius). Specifically, we predicted that bills in geographies where kestrels consumed a larger proportion of vertebrates would be shorter and wider, with a larger tomial tooth. We reviewed the literature on kestrel diets across their range and quantified potential differences in bill shape using geometric morphometric methods for 245 museum specimens. The literature review revealed that most prey consumed by kestrels in North, South, and Central America were invertebrates (51.6–69.1%), whereas Caribbean kestrels consumed mostly vertebrates (61.4%), most of which were reptiles (77.3%). Morphometric analyses agreed with these findings; bill shape differed for island versus mainland kestrels but not among mainland regions. Bill shape on islands reflected a more robust bill with a larger tomial tooth, but had a longer hook, which we suggest is adaptive for consumption of lizard prey, more available on islands due to reduced competition with other raptors compared to mainland regions.
... There is little known about the activities of eagles after fledging and before nesting (Brown 1955;Brown and Amadon 1968). Our data on Bald Eagles (Haliaeetus leucocephalus) raised in Saskatchewan, show they migrate south to the western half of the United States, with many returning to spend their summers as subadults at or near the lake where they were raised (Gerrard et al. , 1978. ...
... For very many years I have been interested in, and concerned about, the correct names of vultures (particularly in Latin), and also the sequence of the species in any list. I first delved into this with Mundy (1984), considering at that time that the important works were Brown & Amadon (1968) and Stresemann & Amadon (1979). One of the big arguments back then was whether the Cathartid (New World) vultures were storks (e.g. ...
... Approximately 50% of the studied nests faced a northerly direction, and nest diameters ranged from 1 to 1.5 meters (Clouet & Goar 2006). Brown & Amadon (1968) reported that the number of eggs in a clutch varied from 1 to 4, with clutches of 2 being the most common. According to Watson (1997), young eaglets typically remain in the nest for about 70 days. ...
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This paper investigates the diet and breeding parameters of the Golden eagle in southwestern Algeria. A synthesis of observations of food remains found in four Golden eagle nests in southwest Algeria from 2020 to 2022 is given. During the breeding season, eagles in the study area fed their young predominantly with Alectoris barbara (RA = 41.6%), followed by Lepus capensis. The aves category accounted for 48% of the food. Among mammals comprising 31%, hare was the main prey with 26%. The results indicate that 100% of the Golden eagles studied in this work preferred mountainous habitats and steep rocky areas to build their nests. The female laid her first egg in the first week of January. The average clutch size, according to the nests studied, is 50% with one egg and 50% with two eggs per brood raised.
... In accordance with other studies (Cramp & Simmons 1980, Arkumarev et al. 2018), we confirm that in most of the cases incubation starts between the 18th and 23th of April and the incubation period lasts 41.8 days. The Egyptian vulture is a species that usually lays two eggs (Brown & Amadon 1968, Cramp & Simmons 1980, Naoroji 2006, of which one usually hatches (Naoroji 2006). Our results support these findings. ...
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The Egyptian vulture (Neophron percnopterus) is a globally endangered species distributed in Eurasia and Africa, with a declining population in most of its range. Even though the species is well-studied, some aspects of its breeding behaviour, more precisely the share of parental care between the sexes within the pair (i.e. nest building, incubation, food provisioning), still remain poorly documented. We used trail cameras as a tool to monitor the breeding behaviour of six Egyptian vulture pairs in Bulgaria during 22 breeding attempts between 2011 and 2021. We found that the male contributes more than the female to the nest arranging (χ 2 = 4, p = 0.04), and females participate less in nest buildings than males (χ2= 92.5, p < 0.05). The rate of copulations recorded in the nest is similar throughout the years (H = 11.95, df = 7, p = 0.1). Both sexes seem to contribute almost equally (7.14 ± 0.126 SD hours per day on average for the female and 5.87 ± 0.123 SD on average for the male) to the incubation across the entire period (χ 2 = 0.125, p = 0.72). Only 23% of the food delivered to the nest would be found in the remains at the end of the breeding season.
... [Traducció n del equipo editorial] INTRODUCTION Although Golden Eagles (Aquila chrysaetos) have a Holarctic distribution that is well described (Brown andAmadon 1968, Katzner et al. 2020), the species can be hard to detect in some regions and, thus some details of that global distribution are poorly understood, including for the parts of the range in eastern North America. In the USA, the Golden Eagle is a year-round resident across much of the West, with northern migratory populations inhabiting both the eastern and western USA during winter. ...
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Golden Eagles (Aquila chrysaetos) have a Holarctic distribution, but some details of that overall distribution are poorly understood, including parts of the range in eastern North America. Recent studies in the region suggest that Golden Eagles may be more widely distributed than previously recognized. For species specific conservation efforts to be effective, an understanding of the distribution of the species is essential. Thus, the goal of this study was to map the winter distribution of Golden Eagles in the eastern half of the USA. To accomplish this, we reviewed and compiled 11,981 Golden Eagle records from eight data sources, including literature and ornithology records, community science data, survey data, and telemetry data. We found that Golden Eagles were observed in winter in each of the 31 states that lie completely east of the 100th meridian and in 1244 of the 2045 counties (61%) in those states. The proportion of counties with records varied by physiographic province, with higher proportions in physiographic provinces with more rugged terrain and greater forest cover. Our study shows that Golden Eagles are more widely distributed during winter in eastern USA states than was previously recognized. This work provides an important foundation for future management and research at a time when threats to this species are expanding rapidly on the landscape. KEY WORDS: empirical distribution; range map; species' distributions. DISTRIBUCIÓ N INVERNAL DE AQUILA CHRYSAETOS EN EL ESTE DE EEUU RESUMEN.-Si bien Aquila chrysaetos tiene una distribución holártica, algunos aspectos de su distribución en el este de América del Norte no son del todo claros. Estudios recientes en la regió n sugieren que su distribución puede ser más amplia que la distribució n previamente reconocida. Para que los esfuerzos p Corresponding author: trish.miller@consciglobal.org 522 de conservació n para una especie en particular sean efectivos, es esencial comprender su distribución. Así, el objetivo de este estudio fue elaborar un mapa de la distribución invernal de A. chrysaetos en la mitad oriental de EEUU. Para esto, revisamos y compilamos 11,981 registros de A. chrysaetos provenientes de ocho fuentes de datos, incluyendo literatura y registros ornitológicos, datos de ciencia comunitaria, datos de censos y datos de telemetría. Encontramos que A. chrysaetos fue observada en invierno en cada uno de los 31 estados que se encuentran completamente al este del meridiano 100 y en 1244 de los 2045 condados (61%) de estos estados. La proporción de condados con registros varió según la provincia fisiográfica, con proporciones más altas en provincias fisiográficas con terreno más accidentado y mayor cobertura forestal. Nuestro estudio muestra que la distribución de A. chrysaetos durante el invierno en los estados del este de EEUU es efectiva-mente más amplia que la previamente reconocida. Este trabajo proporciona una base importante para la gestión e investigación futura en un momento en que las amenazas para esta especie se están expandiendo rápidamente en el paisaje.
... Early studies proposed that Old World vultures are monophyletic (Brown and Amadon, 1968) or polyphyletic with Neophron, Gypaetus, and Gypohierax, forming one or more clades separate from the other Accipitrids (Mundy et al., 1992;Seibold and Helbig, 1995;Lerner and Mindell, 2005;Mindell et al., 2018;Urantowka et al., 2021). Current taxonomists tend to favor the latter contention, with Old World vultures divided into two subfamilies: Gypaetinae and Aegypiinae, with the former positioned at the base of the Accipitrid tree (Wink, 1995;Lerner and Mindell, 2005). ...
Article
Vultures are the only obligate scavengers among extant vertebrates. They provide valuable ecological services in ecosystems through removing carcasses, thus preventing the growth of other scavenger populations and the spread of pathogens. Moreover, their specific diets expose them to various deadly pathogens, which makes them potential candidates for studying molecular adaptations required to survive this extremely specialized scavenging habit. In this review, we summarize the morphological characteristics and behavioral habits, origin and phylogeny, and molecular adaptations to scavenging in both Old and New World vultures. The two groups of vultures share a similar appearance, indicative of convergent evolution. Vultures have experienced different degrees of specialization in their sensory organs; Old World vultures depend on sight, while New World ones depend on both smell and sight. Combined fossil records and molecular data suggest that vultures evolved independently, with distinct phylogenetic positions. We also explored their adaptation to scavenging in facial and intestinal microbiomes, gastric acid secretion and immunity. Compared with the facial microbiome, the intestinal microbiome had a lower diversity, dominated by Fusobacteria and Clostridia. The phages and single invertebrate species Adineta vaga, which feeds on dead bacteria and protozoa, present in the gut suggest a possible alternative defense mechanism. Several genes involved in gastric acidic secretion (including ATP4B, SLC26A7 and SST) and immunity (including BCL6, STING, and TLRs) undergoing positive selection likely have essential roles in eliminating invasive pathogens and initiating an innate immune response. Taken together, this review presents the current research status of vultures and highlights the use of vultures as a model for exploring molecular adaptations of dietary specialization in birds. It also provides a theoretical basis for the study of the genetic mechanisms of vultures to scavenging, and contributes to the formulation of vulture conservation strategies.
... Pacific bazas (Aviceda subcristata), a species of Australian hawk, and the oriental honey-buzzard (Pernis ptilorhynchus), known to specialize in consuming bees and wasps, were documented consuming fruit (Fitzsimons and Leighton, 2021). Previous literature reviews by Brown and Amadon (1968), Ferguson-Lees and Christie (2001), and Fitzsimons and Leighton (2021) synthesizes 13, 18, and 29 species of fruit-eating raptors, respectively. Recently, Barbary macaques (Macaca sylvanus) were observed hunting and consuming rabbits, chicks, and eggs, despite Barbary macaques having never previously been known to eat vertebrates (Young et al., 2012). ...
Article
We present evidence for the first documentation of consumption of a water oak (Quercus nigra) acorn by an eastern screech owl (Megascops asio). A screech owl diet typically consists of small mammals, small birds, and arthropods. In our study, we had a 1-m x 1-m sand pad under observation from a game camera that was set on a 1-min time-lapse delay. On this sand pad, we placed five water oak acorns. In a series of six images over six minutes, we observed an eastern screech owl land near the sand pad, walk to an acorn, and appear to consume the acorn. Although there could be other plausible explanations and events that transpired between 1-min image intervals, we believe this acorn was consumed by the eastern screech owl. The importance of this addition of food type to the diet of a raptor is largely unexplored and undocumented.
... Consequently, this point emphasizes the importance of humility and having or developing social abilities necessary to discuss the subjects of study with your peers. The second point: two monumental monographs by Brown and Amadon (1968) and Mundy et al. (1992) have provided an effective model to describe the essential ecology of these full-time obligate scavengers, facilitating Bildstein's work on vultures at a global scale. The takehome message here is that regardless of the age of the reference, older literature can provide critical insight into the current knowledge of the subject of study. ...
... Both eagles are monotypic and the only members of the subfamily Harpiinae in the Neotropics (Lerner & Mindell 2005;Brown & Amadon 1968). Generally, the Crested Eagle feeds on smaller and more diverse prey than the Harpy Eagle, mainly arboreal snakes, small primates, opossums, and birds (Whitacre et al. 2012;Gomes et al. 2021), whereas Harpy Eagle diet is largely comprised of large arboreal mammals, primarily sloths and primates (Aguiar-Silva et al. 2014;Miranda 2015;Miranda et al. 2021). ...
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Quantifying resource partitioning between co-occurring species can provide insight into processes facilitating coexistence by closely related species, a fundamental question in ecology. We tested whether the habitat requirements of two closely related Neotropical forest eagles, the Crested Eagle (Morphnus guianensis) and Harpy Eagle (Harpia harpyja), differ at fine and coarse resolutions across their shared geographic range. Using landcover and topographic covariates, we first quantified potential resource overlap using higher resolution (30 arc-sec, ~1-km2 data) generalized linear models (GLMs), and second using coarser-grain (2.5 arc-min, ~4.5-km2 data) environmental ordination to capture the potential effect of scale on habitat overlap. The distribution of both eagles was largely explained by canopy tree species richness and canopy structural complexity, with peak suitability of 60-80 % evergreen forest cover. Both eagles were negatively associated with mosaic forest and cultivated areas. From the GLMs, habitat overlap was > 93 % in geographical space but reduced to 73 % when considering environmental space, a proxy for resource overlap. From ordination (Principal Component Analysis), resource overlap was 67 % in environmental space, with randomization tests supporting equivalent environmental space for both eagles. Our results suggest that at the continental scale, Crested and Harpy Eagles share identical environmental space when quantified at fine and broad scales, with little difference in distribution and habitat use. At the continental scale used here both eagles can co-exist, presumably with sufficient habitat heterogeneity for coexistence when they occur in close proximity. Therefore, further research is required at the local-level to fully capture where coexistence at the local-scale is facilitated more by fine scale habitat selection, or difference in diet between two species with indistinguishable habitat use.
... Ridgely & Greenfield (2001) illustrated adult Bay-winged Hawk with the dark remiges of Harris's Hawk. Brown & Amadon (1989) showed adult Harris's Hawk and juvenile Bay-winged Hawk, but did not indicate the taxon in either case. Del Hoyo et al. (1994) depicted adults of both taxa, but did not describe differences in juvenile plumages or the Basic II and Basic III plumages of Bay-winged Hawk. ...
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The two main populations of Parabuteo unicinctus have long been treated as subspecies of the same species: Harris's Hawk P. u. harrisi in the southern USA to Costa Rica, and Bay-winged Hawk P. u. unicinctus in South America. However, they differ considerably in their morphology, number of plumages, and behavioural ecology. Adult Harris's Hawk differs in multiple plumage characters from adult Bay-winged Hawk, and differences are even more marked in juvenile plumage. Harris's Hawk has two age-related plumages but Bay-winged Hawk shows delayed plumage maturation and has four such plumages. Harris's Hawk breeds and hunts cooperatively, whereas Bay-winged Hawk nests only in pairs, and hunts individually. There are no valid records of Harris's Hawk in South America. We believe that the differences in adult and juvenile plumages, the number of immature plumages, and differences in breeding and hunting mean that Harris's Hawk and Bay-winged Hawk are best treated as separate species.
... No he encontrado referencias sobre nidificaeión otoñal o invernal para esta especie, cuyos hábitos de cría han sido resumidos por Brown y Amadon (1968). Especies australianas de Elanus pueden nidificar en esa época del año, según datos resumidos por estos autores. ...
... The nearest other subspecies (B. l. texanus) is found in coastal southern Texas and northeastern Mexico and is separated from elegans by approximately 1700 km (Brown and Amadon 1968). In effect, subspecies elegans is an insular population surrounded by the Pacific Ocean to the west, desert to the south and east, and unfavorable coniferous woodlands to the north (Fig. 1). ...
... However, if one partner gets severely injured or dies, the other will find a new mate [22]. The species has a strong nest-site fidelity, and during the nonbreeding years the pair maintain their bond by repairing nests or building new ones [36]. Territories often have several alternative nests, and, while some pairs may use a single nest throughout their breeding, others may alternate between nests more frequently [14,37]. ...
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Estimating turnover in a population provides information on population dynamics, such as dispersal and mortality. Dispersal increases genetic diversity and affects the genetic structure. Golden eagles are monogamous, tend to mate for life, and have strong nest site fidelity, which suggests low turnover rates. Here, we first studied genetic diversity and population structure in the Finnish golden eagle population using 11 microsatellite loci and a fragment of a mitochondrial DNA control region. We found no notable changes in genetic diversity during the 15-year study period and did not discover any population structure. Then, we examined the turnover rate using chick genotypes (N = 935) by estimating relatedness between chicks born in the same territory in different years. The results showed a turnover rate of 23%, which correlated with the breeding success of the previous year. Similarly, in the absence of turnover, the pair changed nest sites within a territory after an unsuccessful breeding. In addition, our dataset also revealed natal dispersal of ten individuals. Natal dispersal distance was 110 km on average (median 98 km); however, the distance seemed to vary depending on geographical location, being greater in Northern Finland than in Southern Finland.
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I recorded information on pre-roost habitats of Western Marsh Harriers (Circus aeruginosus) near communal roost sites located in and around Keoladeo National Park (KNP), India, during three winters from 1997 to 2000. Harriers pre-roosted in different habitats in KNP compared to the surrounding areas (25-km radius). Harriers used trees as their main pre-roosting perches in KNP, but mainly used open fields in the surrounding areas. All nine tree species present near roost sites in KNP were used for pre-roosting. Among tree species used for pre-roosting, harriers preferred sacred fig (Ficus religiosa), a tall tree with a wide canopy. Babul (Vachellia nilotica) trees, though not preferred, were more utilized for pre-roosting, probably because of their abundance. The lack of suitable open areas near the primary roost site in KNP may help explain why harriers used trees as pre-roosting perches there. At other roost sites outside KNP where trees were sparse, harriers mainly pre-roosted on the ground. By perching on trees, harriers may be conspicuous to other arriving harriers, which likely helps the birds gather into a large roosting flock. Such large roosts may benefit harriers by providing protection from predators and a site where birds may obtain information on food resources. Although trees were used as pre-roosting sites at KNP, I did not observe any harriers roosting on trees overnight during the 3-yr study.
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We describe for the first time the visual fields of the largest tropical raptor, the Harpy Eagle (Harpia harpyja), a powerful keystone species that hunts almost exclusively in forested habitats. They have the largest blind area described to date of any diurnal raptor species, and relatively narrow binocular fields, which together may help explain the way they interact with their prey in the visually complex environments they inhabit. As a top predator, their spatial visual sampling is likely driven more by foraging needs than predator detection, and they thus serve as an excellent study species for understanding the tradeoffs between visually guided foraging and anti-predatory behaviors. Further studies on the position and the projection of retinal foveae, visual acuity, and color vision will improve our understanding of their visual capabilities and could play important roles in conservation of a vulnerable Neotropical species.
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