The ornate hawk-eagle (Spizaetus ornatus) is a 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.Friedmann H. (1935). A new race of the Crested Hawk-eagle Spizaetus ornatus. Journal of the Washington Academy of Sciences, 25 (10): 450-451. 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.Lerner, H., Christidis, L., Gamauf, A., Griffiths, C., Haring, E., Huddleston, C.J., Kabra, S., Kocum, A., Krosby, M., Kvaloy, K., Mindell, D., Rasmussen, P., Rov, N., Wadleigh, R., Wink, M. & Gjershaug, J.O. (2017). Phylogeny and new taxonomy of the Booted Eagles (Accipitriformes: Aquilinae). Zootaxa, 4216(4), 301-320. 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.Clark, W. S., & Schmitt, N. J. (2017). Raptors of Mexico and Central America. Princeton University Press. 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 ornate hawk-eagle female lays almost always a single egg and the species has a fairly prolonged breeding cycle like many tropical raptors, especially due to a lengthy post-fledging stage on which juveniles are dependent on their parents.Phillips, R. A., & Hatten, C. J. (2013). Nest observations on the Ornate Hawk-Eagle (Spizaetus ornatus) in Belize, Central America. Boletin SAO, 22. It is a diversified and exceptionally powerful predator which takes a range of prey, usually various medium-to-large-sized birds and small-to-medium-sized mammals as well as occasional reptiles.Klein, B. C., Harper, L. H., Bierregaard, R. O., & Powell, G. V. (1988). The nesting and feeding behavior of the ornate hawk-eagle near Manaus, Brazil. The Condor, 90(1), 239-241. Like many forest-dependent raptors, especially those in the tropical and subtropical regions, this species is likely under the pressing threat of deforestation. The decline of forest habitat in this species range, especially the Amazon rainforest, led the IUCN to uplist the ornate hawk-eagle as Near Threatened in 2016.
Taxonomy The ornate hawk-eagle is a member of the booted eagle subfamily, with the signature well-feathered tarsi present on both tropical and temperate species (and shared, presumably through convergent evolution, with a pair of buteonine hawks). It is one of four living members of the Spizaetus genus of "hawk-eagle" native to the neotropics. At one time, Old World hawk-eagles, native to various southern areas of Asia, were also included in the Spizaetus genus. However, genetic studies have shown the Asian group of species to be paraphyletic, resulting in the Old World members being placed in Nisaetus (Hodgson, 1836) and separated from the New World species.Helbig, A.J, Kocum, A., Seibold, I. & Braun, M.J. (2005). A multi-gene phylogeny of aquiline eagles (Aves: Accipitriformes) reveals extensive paraphyly at the genus level. Molecular Phylogenetics and Evolution 35(1):147-164.Haring, E., Kvaløy, K., Gjershaug, J. O., Røv, N., & Gamauf, A. (2007). Convergent evolution and paraphyly of the hawk‐eagles of the genus Spizaetus (Aves, Accipitridae)–phylogenetic analyses based on mitochondrial markers. Journal of Zoological Systematics and Evolutionary Research, 45(4), 353-365.
The history of the American Spizaetus genus has been indicated by the diversity of hawk-eagles found in the fossil records in the United States and Mexico. At least five such species have been described, having presumably radiated from basal hawk-eagles of Asian origin across the Bering Land Bridge. Some of these are ancestors of modern Spizaetus species, with the genera having been present in North America at least since the Pliocene.Martin, L. D. (1975). A new species of Spizaetus from the Pliocene of Nebraska. The Wilson Bulletin, 87(3), 413-416.Martin, L. D. (1971). An early Pleistocene eagle from Nebraska. The Condor, 73(2), 248-250. Some forms were considerably more massive than any extant hawk-eagle and indeed were likely to have exceeded the size of any living booted eagle. Fossil species such as Spizaetus willetti may have grown to similar sizes as the modern harpy eagle (Harpia harpyja).Howard, H. (1935). A new species of eagle from a Quaternary cave deposit in eastern Nevada. Condor 37:206-209.Howard, H. (1962). Bird remains from a prehistoric cave deposit in Grant County, New Mexico. The Condor, 64(3), 241-242.
Genetic markers indicate the black-and-white hawk-eagle (Spizaetus melanoleucus) and especially the black-and-chestnut eagle (Spizaetus isidori) are closely related to the ornate hawk-eagle, resulting in their respective former genera of Spizastur and Oroaetus being eliminated. The fourth neotropical hawk-eagle, the black hawk-eagle (Spizaetus tyrannus), has been found to be basal to the other extant species. Per genetic research, the ornate hawk-eagle and black-and-chestnut eagle are considered as sister species.
The ornate hawk-eagle has two subspecies. The nominate subspecies (S. o. ornatus) occupies much of the South American range of the species, including eastern Colombia, Venezuela, and all of the species' range in Brazil and points south. The second subspecies, S. o. vicarius, has been described to inhabit the discontinuous northern part of the range, extending from Mexico and Central America south through much of western Colombia and western Ecuador and as far south as El Oro.Iliff, M. (2010). Ornate Hawk-Eagle (Spizaetus ornatus), Neotropical Birds Online (TS Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology. The subspecies seem to differ mostly in the plumage characteristics of adults. Whereas the nominate birds are a more cinnamon-hued color on the neck with slightly paler ground color and sparser markings about the head and undersides, S. o. vicarius, tends to be darker overall, with a richer, deeper. more rufous color around the neck, denser and darker markings overall, and broader bands on the tail.de Schauensee, R. M. (1950). Colombian Zoological Survey. Part VII: A Collection of Birds from Bolivar, Colombia. Proceedings of the Academy of Natural Sciences of Philadelphia, 102, 111-139.
Description
This is a medium to large-sized species of raptor, but small for an eagle. In the ornate hawk-eagle, the sexes are similar in appearance and overlap in size, but like most birds of prey, do show reverse sexual dimorphism, in which females outsize males to the contrary of most nonraptorial birds. The biggest female ornate hawk-eagles are 13% larger than the biggest males, with an average of about 8% greater in nominate race. In Central America, in extreme cases, the largest females are as much as 50% heavier than the smallest males. The species is slightly smaller than the largest members of widespread raptor genera such as the largest Buteo and Falco species, but is usually larger than other forest raptors in its range apart from vultures and other eagle species.
The total length of full-grown ornate hawk-eagle is .Howell, S. N., & Webb, S. (1995). A guide to the birds of Mexico and northern Central America. Oxford University Press. Average total length is estimated at for males and for females.Vallely, A. C., & Dyer, D. (2018). Birds of Central America: Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, and Panama (Vol. 136). Princeton University Press. The wingspan may range from . Body mass can vary in males from and in females from . The average weight of five adult males was while another five males averaged .Whitacre, D. F., & Jenny, J. P. (2013). Neotropical birds of prey: biology and ecology of a forest raptor community. Cornell University Press. The average weight of four adult females was , while a sample of 11 averaged . Among standard measurements, wing chord measures from in males and in females against S. o. vicarius in which wing chord is known to measure in males and in females.
In tail length, males vary from and females from . The culmen from cere measures in males and . In tarsus length, males may measure and females may measure . Average wing chord lengths from Guatemala (S. o. vicarius), showed seven males to average and eight females to average . Meanwhile, in the same sample, mean tail length was in males and in females and mean tarsal length was and in the sexes, respectively. The largest rear talon (or hallux claw) present on all accipitrids (usually the main killing tool in these predators' arsenal) is particularly enlarged on the ornate hawk-eagle relative to its size, averaging about in males and in females from Guatemala, with an average foot span for both sexes measuring around .
Ornate hawk-eagles largely perch within the tree canopy, but sometimes are out on exposed branches, especially earlier in the morning. Usually soaring activity peaks in the late morning. Brown & Amadon (1986) described the species are "rather stolid and buteonine, despite the long tail and crest".Brown, Leslie and Amadon, Dean (1986). Eagles, Hawks and Falcons of the World. The Wellfleet Press. . Adults are largely distinguishable by their rufous cowls and bold barring below.Fagan, J., & Komar, O. (2016). Peterson field guide to birds of northern Central America. Houghton Mifflin Harcourt.
Furthermore, all ornate hawk-eagles bear a long, erectile crest, which may variously be laid flat against the head, protrude straight up like a spike, or sometimes hang at a slight curve. Adults when perched have an obvious black crown, crest, and malar stripes (continuing to sides as isolated streaks), set off by the rufous color on their cheeks, ear coverts, and sides of the neck and chest (sometimes completely covering their upper chests), the rufous shading into a somewhat browner rufous nape. On the upperside, they are barred blackish to dark brown with usually apparent white tips on the mantle and lesser wing coverts. Meanwhile, on the underside, they have a whitish base color, which other than the often-plain throat, is boldly overlaid with black barring, which extends down to the abdomen and legs, while the crissum is spotted black.
Like many forest raptors, the species has relatively short wings and a longish tail.Van Perlo, B. (2009). A field guide to the birds of Brazil. Oxford University Press. When perched, their wing tips slightly exceed their tail base. The tail is blackish with a creamy whitish tip and three broad pale bands, which are greyish above and whitish below, the basal bar often being obscured. According to Brown & Amadon "the perched bird seemingly has legs set very far forward, almost under the chest, thus giving the impression of posed readiness. The position of the black crest hints at the bird's temper at the moment". Juvenile differ conspicuously in many respects, generally lacking most of the pigment visible in adults. Juveniles lack the adults' rufous collar, malar stripes and underside barring. Instead, the juvenile's whole head and underparts are white excepting thin black streaks on the crown and the tip of their crest.