Black-and-chestnut eagle | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Accipitriformes |
Family: | Accipitridae |
Genus: | Spizaetus |
Species: | S. isidori |
Binomial name | |
Spizaetus isidori (Des Murs, 1845) | |
Synonyms [2] | |
Oroaetus isidori(Des Murs, 1845) |
The black-and-chestnut eagle (Spizaetus isidori), also known as Isidor's eagle, [2] is a large South American species of bird of prey in the family Accipitridae. It is often placed in the monotypic genus Oroaetus. [2] However, recent genetic testing indicates that this species is fairly closely related to Spizaetus species and thus the species should be included in that genus. [3] The black-and-chestnut eagle is a typical forest raptor, hunting primarily small to medium-sized mammals and birds and constructing a large nest in a tall tree. [4] Unfortunately, the twin causes of habitat destruction and persecution, justified or not as an occasional poultry killer, have caused strong population declines and the black-and-chestnut eagle is considered to be an Endangered species by the IUCN. [1] [4]
This is a fairly large eagle and very large raptor at 60 to 80 cm (24 to 31 in) in total length with a wingspan of 147 to 180 cm (4 ft 10 in to 5 ft 11 in). It is largest current member of the genus Spizaetus , with the smallest males somewhat larger linearly than the largest female ornate hawk-eagles. [5] [6] [7] Full grown weights for black-and-chestnut eagles have been reported as 1.5 to 3.5 kg (3.3 to 7.7 lb), [7] making it among neotropic eagles around the same body size as the two largest Buteogallus and the black-chested buzzard-eagle, at least twice as heavy as other Spizaetus and slightly heavier than the notably longer crested eagle. Only the harpy eagle is considerably larger among all neotropical eagles, with most other eagles absent from the high elevation forest home of the black-and-chestnut eagle apart from the solitary eagle. [8] [9] For its genus and for many genera of forest-dwelling raptors in general, it has a proportionately short tail and proportionately long wings but still it is longer tailed and shorter winged than most true open country eagles. [6] Females are notably larger as is typical in raptors, by about 4% to 14%, and longer tailed. The wing chord and tail length is 463 to 488 mm (18.2 to 19.2 in) and 283 to 300 mm (11.1 to 11.8 in) in males, respectively, and 508 to 528 mm (20.0 to 20.8 in) and 329 to 335 mm (13.0 to 13.2 in) in females. A small sample of these eagles measured 110 to 120 mm (4.3 to 4.7 in) in tarsus length. [9] The talons of this species are very large and formidable for the size of the eagle, averaging 50.9 mm (2.00 in) in 6 females and 46.4 mm (1.83 in) in 6 males along the enlarged hallux claw (their main killing apparatus), thus nearly as large as a much bigger eagle such as a golden eagle. [10]
As an adult, this species is glossy black on the head and the back and a rich and somewhat streaky chestnut on the underside, much of the wing secondaries and even on its legs. The black-tipped white feathers on the wing primaries contrast strongly with the chestnut secondaries and underwing coverts. The adult's tail is grayish with a thick black subterminal band. Adult black-and-chestnut eagles have orange-yellow eyes and yellow bare parts but for the somewhat proportionately small gray bill. [6] [9] [11] The juvenile bird is very different, being whitish over the head and body with a buffy wash underneath and scaly grey-brown on the back and mantle, somewhat more extensive than in other whitish juvenile Spizaetus. The wings are whitish on juveniles where adults are chestnut and the remaining wing feathers of the juvenile have a much more varying black-and-white pattern. The tail of juveniles has two strong black bands. The juvenile’s eye is blue-gray, later becoming yellow before becoming orangish at maturity. Maturity is obtained gradually over four years, about average for a large eagle but nearly twice as long as some other Spizaetus species. [6] [9] [12] Adult black-and-chestnut eagles are practically unmistakable, unless seen only dorsally and then can be distinguished from the black hawk-eagle by its larger, much bulkier frame and distinctive tail pattern on a conspicuously relatively shorter tail. Black-and-chestnut juveniles are more reminiscent of juveniles of both other Spizaetus species but are distinctly larger, bulkier and proportionately shorter tailed than both and each species has somewhat distinctive juvenile patterns on the wing primaries and tail. The black-and-white hawk-eagle is particularly far smaller and, unlike the ornate hawk-eagle, is not known to take up occasional residency in cloud forests. Also juvenile pale morph crested eagles can appear surprisingly similar in flight to juvenile black-and-chestnut eagles but are conspicuously longer tailed with a stronger barring pattern. Furthermore, there is little to no overlap with the other species of the genus as well as crested eagles due to the distinct habitat used by the black-and-chestnut. [9] [13] The solitary eagle is unlikely to be mistaken, being much broader winged and lacks all chestnut pigment, furthermore having an almost inverse tail pattern to adult black-and-chestnuts on a rather shorter tail. [9] Unlike other crested raptors, it is reported that the crest of the black-and-chestnut eagle is held upright during calm periods of time and in flight and more likely to be held flat in stressful circumstances. [6]
Nest building is February and March, laying eggs in April and May and fledgling young by August and September. It builds a huge stick nest about 2 m (6.6 ft) across and 1 m (3.3 ft) deep. Clutches include 1 to 2 fledglings. At the nest area in some areas, adults primarily appeared to bring squirrels to feed their young. In Argentina, it was recorded that the female visited the nest more times and invested more time into nest building than males do. The female was responsible for the incubation and incubated every night in Argentina, while the male provided preys for both and briefly incubated when the female went out of the nest. After hatching, the female does all of the chick covering, feeding and defense were only carried out by the female, whereas the male provided prey. These are typical parental behaviors by raptors and eagles, but seem somewhat more rigidly divided in this species as the male never appears to take on brooding responsibilities in the black-and-chestnut eagle. [14]
Black-and-chestnut eagle hunts primarily in the canopy; soars frequently and is rarely seen perched. Powerful legs and talons specialized for taking large prey. [15] They frequently have much-abraded tails by plunging after prey through the branches. Main prey is usually small-to-mid-sized arboreal mammals including red-tailed squirrels (Sciurus granatensis), opossums (Didelphis sp.), and stump-tailed porcupines (Coendou rufescens). [16] Occasionally, carnivorans such as kinkajous (Potos flavus), coatis (Nasuella olivacea & Nasua nasua) are taken as well as monkeys such as gray-bellied night monkeys (Aotus lemurinus), tufted capuchin (Sapajus apella), and even woolly monkeys (Lagothrix lagothricha). [16] [17] [18] [19] Birds are import prey in some regions, mainly guans such as Andean guans (Penelope montagnii) and Sickle-winged Guans (Chamaepetes goudotii), though smaller birds such as Band-tailed pigeons (Patagioenas fasciata) are also taken. [16] [17] Black-and-chestnut eagles sometimes hunt chickens, including standard-sized adults, which has caused some persecution of this endangered species. One small dietary study was conducted in Colombia, however, found that chickens made up 14.7% while wild Andean guans were much more frequently taken, making up 53.9% of the diet. Also, here the black-and-chestnut eagles took about the same number of western mountain coatis as they did chickens, and coatis are known predators of poultry chicks and eggs. [17] [20]
They overlap in range with several other large forest eagles, including other Spizaetus eagles, but few interactions have been reported and, as they often occur at slightly different altitudes than other neotropic forest eagles, the black-and-chestnut eagle is believed to be normally the top avian predator in its range. One exception is the similarly sized solitary eagle, which preliminary reports suggests mostly hunts snakes, whereas the black-and-chestnut eagle seems to prefer birds and small-to-mid-sized mammals, and the two species were observed flying near each other without aggression in southeastern Peru since prey partitioning appears to allow them to co-exist. [19] One species seen to be aggressively displaced by the black-and-chestnut eagles here was the turkey vulture, possibly because they sometimes steal eggs from bird's nests. [19]
It is found in humid montane forests, normally at elevations between 1,800 to 2,500 m (5,900 to 8,200 ft), in the Andes from northern Argentina, through Bolivia, Peru, Ecuador, Colombia, to Venezuela, with isolated populations in the Venezuelan Coastal Range, Serranía del Perijá and Sierra Nevada de Santa Marta. It is generally local and rare. Widespread cutting of primary forest in foothills throughout the Andes is the primary cause of the precipitous decline of this species. Deforestation in the forests of the Andes is rampant as in much of the tropics. [21] [22] [23] There may be only 370–1500 individuals of black-and-chestnut eagles left in the wild (and 250–999 mature individuals), fewer than previously thought. It is one of the most endangered birds of prey in the Americas. [24] Further exacerbating the species' conservation issues are its continued persecution as a killer of domestic fowl. [17] The black-and-chestnut eagles are a control species because they help to maintain the balance of ecosystems by hunting other animals for food(Nest Discovered in Argentina Reveals Potential Human–Predator Conflicts).
The eastern imperial eagle is a large bird of prey that breeds in southeastern Europe and extensively through West and Central Asia. Most populations are migratory and winter in northeastern Africa, the Middle East and South and East Asia. Like all eagles, the eastern imperial eagle is a member of the family Accipitridae. Furthermore, its feathered legs mark it as a member of the subfamily Aquilinae. It is a large, dark-colored eagle, with a resemblance to other members of the genus Aquila but it is usually the darkest species in its range. This is an opportunistic predator that mostly selects smallish mammals as prey but also a fairly large proportion of birds, reptile and other prey types, including carrion. Compared to other Aquila eagles, it has a strong preference for the interface of tall woods with plains and other open, relatively flat habitats, including the wooded mosaics of the steppe. Normally, nests are located in large, mature trees and the parents raise around one or two fledglings. The global population is small and declining due to persecution, loss of habitat and prey. It has therefore been IUCN Red Listed as Vulnerable since 1994.
The wedge-tailed eagle also known as the eaglehawk, is the largest bird of prey in the continent of Australia. It is also found in southern New Guinea to the north and is distributed as far south as the state of Tasmania. Adults of the species have long, broad wings, fully feathered legs, an unmistakable wedge-shaped tail, an elongated upper mandible, a strong beak and powerful feet. The wedge-tailed eagle is one of 12 species of large, predominantly dark-coloured booted eagles in the genus Aquila found worldwide. Genetic research has clearly indicated that the wedge-tailed eagle is fairly closely related to other, generally large members of the Aquila genus. A large brown-to-black bird of prey, it has a maximum reported wingspan of 2.84 m and a length of up to 1.06 m.
The greater spotted eagle, also called the spotted eagle, is a large migratory bird of prey in the family Accipitridae.
The African hawk-eagle is a large bird of prey. Like all eagles, it belongs to the family Accipitridae. This species' feathered legs mark it as a member of the Aquilinae subfamily. The African hawk-eagle breeds in tropical Sub-Saharan Africa. It is a bird of assorted woodland, including both savanna and hilly areas but the tend to occur in woodland that is typically dry. The species tends to be rare in areas where their preferred habitat type is absent. This species builds a stick nest of around 1 m (3.3 ft) across in a large tree. The clutch is generally one or two eggs. The African hawk-eagle is powerfully built and hunts small to medium sized mammals and birds predominantly, occasionally taking reptiles and other prey as well. The call is a shrill kluu-kluu-kluu. The African hawk-eagle is considered a fairly stable species and a species of Least Concern per the IUCN.
The changeable hawk-eagle(Nisaetus cirrhatus) or crested hawk-eagle is a large bird of prey species of the family Accipitridae. More informal or antiquated English common names include the marsh hawk-eagle or Indian crested hawk-eagle. It is a member of the subfamily Aquilinae, with signature feathers, absent in tropical raptors from outside this subfamily, covering the tarsus. It was formerly placed in the genus Spizaetus, but studies pointed to the group being paraphyletic resulting in the Old World members being placed in Nisaetus and separated from the New World species. It is a typical "hawk-eagle" in that it is an agile forest-dwelling predator and like many such eagles readily varies its prey selection between birds, mammals or reptiles as well as other vertebrates. Among the members of its genus, the changeable hawk-eagle stands out as the most widely distributed, adaptable and abundant species. Individuals show a wide range of variation in plumage from pale to dark, varying with moult and age giving rise to the name "changeable".
The mountain hawk-eagle or Hodgson's hawk-eagle, is a large bird of prey native to Asia. The latter name is in reference to the naturalist, Brian Houghton Hodgson, who described the species after collecting one himself in the Himalayas. A less widely recognized common English name is the feather-toed eagle. Like all eagles, it is in the family Accipitridae. Its feathered tarsus marks this species as a member of the subfamily Aquilinae. It is a confirmed breeding species in the northern part of the Indian subcontinent, from India, Nepal through Bangladesh to Thailand, Taiwan, Vietnam and Japan, although its distribution could be wider still as breeding species. Like other Asian hawk-eagles, this species was earlier treated under the genera of Spizaetus but genetic studies have shown this group to be paraphyletic, resulting in the Old World members being placed in Nisaetus and separated from the New World species. As is typical of hawk-eagles, the mountain hawk-eagle is a forest dwelling opportunistic predator who readily varies its prey selection between birds, mammals and reptiles along with other vertebrates. Although classified currently as a least-concern species due its persistence over a rather wide distribution, this species is often quite rare and scarce and seems to be decreasing, especially in response to large-scale habitat degradation and deforestation.
The ornate hawk-eagle is a fairly large bird of prey from the tropical Americas. Formerly, some authorities referred to this species as the crested hawk-eagle, a name that may cause some confusion as it is more commonly used for an Asian eagle species. Like all eagles, it is in the family Accipitridae. This species has a feathered tarsus that marks it as a member of the Aquilinae or booted eagle subfamily. This species is notable for the vivid colors and bold markings of adults, which differ considerably from the far more whitish plumage of the juvenile bird. The ornate hawk-eagle ranges from central Mexico south through much of Central America and in a somewhat spotty but broad overall range into South America, including in the west apart from the Andes and broadly on the Atlantic side especially Brazil down to as far as Southeast Brazil and northern Argentina. This species is found largely in primary forests with tall trees, although can be found in many forest types.
The bateleur, also known as the bateleur eagle, is a medium-sized eagle in the family Accipitridae. It is often considered a relative of the snake eagles and, like them, it is classified within the subfamily Circaetinae. It is the only member of the genus Terathopius and may be the origin of the "Zimbabwe Bird", the national emblem of Zimbabwe. Adult bateleurs are generally black in colour with a chestnut colour on the mantle as well as also on the rump and tail. Adults also have gray patches about the leading edges of the wings with bright red on their cere and their feet. Adults also show white greater coverts, contrasting with black remiges in males, gray patches on the underwing primaries and black wingtips. The juvenile bateleur is quite different, being largely drab brown with a bit of paler feather scaling. All bateleurs have extremely large heads for their size, rather small bills, large feet, relatively short legs, long, bow-like wings and uniquely short tails, which are much smaller still on adults compared to juvenile birds.
The black-chested buzzard-eagle is a bird of prey of the hawk and eagle family (Accipitridae). It lives in open regions of South America. This species is also known as the black buzzard-eagle, the gray buzzard-eagle, or analogously with "eagle" or "eagle-buzzard" replacing "buzzard-eagle", or as the Chilean blue eagle. It is sometimes placed in the genus Buteo.
The Papuan eagle is a large bird of prey. It is also known by several other names, including Papuan harpy eagle, New Guinea eagle, New Guinea harpy eagle, or kapul eagle, the latter name from the local name for a usually arboreal marsupial that the eagle is known to regularly hunt. This is an endemic species to New Guinea, and it can occasionally be found throughout the island. This is a forest-dwelling species, usually occurring in mature rainforest. The Papuan eagle is a fairly little-known species for a large eagle; however, it is known to prey on a wide range of prey, probably by and large mammals and birds from small to quite large sizes. Unique amongst eagles, the Papuan eagle is a surprisingly fast and agile terrestrial avian predator and is capable of chasing down prey on the forest floor. What little study has been conducted about its breeding habits suggests it nests in a large forest tree, perhaps every other year. The Papuan eagle is probably naturally scarce, but it is under the threat of habitat destruction by deforestation, as well as hunting. Due to its small and declining population, the species has been classified as vulnerable by the IUCN.
The crested eagle is a large Neotropical eagle. It is the only member of the genus Morphnus. The crested eagle can grow up to 89 cm (35 in) long, with a wingspan up to 176 cm (69 in), and weigh up to 3 kg (6.6 lb). The plumage varies between a light brownish-gray to sooty gray or even blackish in some cases. It has a white throat and a dark spot on the crest and a small dark mask across the eyes. It ranges extensively throughout Central and South America, but not in large numbers. favoring tropical lowland forest. A powerful predator, its diet consist mainly of small mammals, rodents, snakes and smaller birds. Despite their large distribution, they are currently classified as Near Threatened by the IUCN, due mainly to habitat loss
The bicolored hawk is a species of bird of prey in the family Accipitridae. It is found in forest, woodland, second growth, plantations, and wooded savanna in southeastern Mexico, Central America, and northern and central South America. Though generally uncommon, it is the most common species of Astur in most of its range, but it does not occur at altitudes above 2,700 metres (8,900 ft) such as the highest parts of the Andes.
The grey-bellied hawk or grey-bellied goshawk is a fairly large and rare species of forest-dwelling South American bird of prey in the family Accipitridae.
The barred hawk is a species of bird of prey in the family Accipitridae. It has also been known as the black-chested hawk.
Cassin's hawk-eagle or Cassin's eagle, is a relatively small eagle in the family Accipitridae. Its feathered legs mark it as member of the Aquilinae or booted eagle subfamily. A forest-dependent species, it occurs in primary rainforests across western, central and (marginally) eastern Africa where it preys on birds and tree squirrels. It was named after John Cassin who first described it in 1865. Due to widespread habitat destruction, its populations are steadily declining but have not yet warranted upgrading its status from Least Concern.
The black-and-white hawk-eagle is a bird of prey species in the eagle and hawk family (Accipitridae). It is found throughout a large part of tropical America, from southern Mexico to northern Argentina.
The collared forest falcon is a species of bird of prey in the family Falconidae. It is the largest member of the Micrastur genus and a common inhabitant of tropical rainforests in Latin America. Hiding in the dense forest canopy, they are a secretive bird often only recognized by their distinctive call. With a morphology or body type allowing them to be agile in their forested habitat, their diet comprises a wide variety of prey from smaller frogs to adult turkeys (2.7-3.2 kg).
The black hawk-eagle, also known as the tyrant hawk-eagle, is a species of eagle found from central Mexico through Central America into the south of Brazil to Colombia, eastern Peru, and as far as northern Argentina. There are two known subspecies, S.t. tyrannus, which is found in Southeastern Brazil and Northeastern Argentina, and the slightly smaller S. t. serus, which can be found elsewhere throughout the species' range. Its preferred habitats include humid and moist forests close to rivers, and several types of woodland. It is uncommon to fairly common throughout most of its range. Its closest relative is the ornate hawk-eagle, which is similar in size, appearance and behavior but lives at lower elevations.
The Aquilinae are a subfamily of eagles of the family Accipitridae. The general common name used for members of this subfamily is "booted eagle", although this is also the common name of a member of the subfamily. At one point, this subfamily was considered inclusive with the Buteoninae based probably on some shared morphological characteristics. However, research on the DNA of the booted eagles has shown that they are a monophyletic group that probably have had millions of years of separation from other extant forms of accipitrid.
The crowned eagle, also known as the African crowned eagle or the crowned hawk-eagle, is a large bird of prey found in sub-Saharan Africa; in Southern Africa, it is restricted to more easterly areas. Its preferred habitats are principally riparian woodlands and various forests. The crowned eagle is the only extant member of the genus Stephanoaetus. A second species, the Malagasy crowned eagle, went extinct after early humans settled on Madagascar.