The bicolored hawk (''Astur bicolor'') is a species of

bird of prey Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...

in the family

Accipitridae The Accipitridae () is one of the four families within the order Accipitriformes, and is a family of small to large birds of prey with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects ...

. It is found in forest, woodland, second growth, plantations, and wooded savanna in southeastern

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

, and northern and central

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

(as far south as northern

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

). Though generally uncommon, it is the most common species of '' Astur'' in most of its range, but it does not occur at altitudes above such as the highest parts of the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

Taxonomy

The bicolored hawk was formally described in 1817 by the French ornithologist Louis Vieillot under the

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...

''Sparvius bicolor''. He specified Cayenne in

French Guiana French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west ...

as the type locality. The bicolored hawk was formerly placed in the large and diverse genus '' Accipiter''. In 2024 a comprehensive

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study of the Accipitridae confirmed earlier work that had shown that the genus was

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

. To resolve the non-

monophyly In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent comm ...

, ''Accipiter'' was divided into six genera. The genus '' Astur'' was resurrected to accommodate 9 species, including the bicolored hawk, that had previously been placed in ''Accipiter''. The resurrected genus had been introduced in 1799 by the French naturalist

Bernard Germain de Lacépède Bernard-Germain-Étienne de La Ville-sur-Illon, comte de Lacépède or La Cépède (; 26 December 17566 October 1825) was a French natural history, naturalist and an active freemason. He is known for his contribution to the Comte de Buffon's g ...

. The genus name is from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''astur'', ''asturis'' meaning "hawk". The bicolored hawk is also closely related to the Cooper's hawk (''A. cooperii'') and Gundlach's hawk (''A. gundlachi''); these three form a superspecies. Until recently, the Chilean hawk (''A. chilensis'') from the colder, southernmost South America was treated as a race of ''A. bicolor'' but due to its differences in habitat preferences and plumages from the bicolored hawk, ''A. chilensis'' is now considered a full species.Accipiter bicolor
Globalraptors.org (2012-07-27). Retrieved on 2013-04-03. Four subspecies are recognised: *''A. b. bicolor'' ( Vieillot, 1817) – found in Southeastern Mexico and south through northern South America. Adults have a black crown, slate upper parts and a blackish tail that displays two or three pale bars. The primaries are obscurely barred. *''A. b. fidens'' (

Bangs Bang, bang!, or bangs may refer to: Products * M1922 Bang rifle, a US semi-automatic rifle designed by Søren Hansen Bang * Bang, a List of model car brands, model car brand * Bang (beverage), an energy drink Geography * Bang, Central African ...

& Noble, 1918) – occurs in Eastern and Southern Mexico. It is morphologically similar to ''A. b. bicolor'', but is larger in size and darker in color. *''A. b. guttifer'' ( Hellmayr, 1917) – located in South Bolivia and northern Argentina. The underparts of the adult are grey or extensively salmon rufous with large white spots and bars. *''A. b. pileatus'' ( Temminck, 1823) – living in Brazil. Adults are similar to ''A. b. bicolor'', but are much paler and have a pearl-grey collar. Under-wing coverts and thighs are rufous.

Description

At in length and in weight, it is significantly smaller than the northern goshawk of

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

and North America, and somewhat smaller than the Cooper's hawk of North America, but it is among the largest hawks in Central and South America (only the rare grey-bellied hawk is larger). As in other hawks, the female is far larger than the male. Adults are grey above with darker wings and crown, and a banded tail. The underparts typically vary from dark grey to very pale grey, but the southern subspecies can sometimes be rufescent below. The thighs are always pure rufous (not always easily seen), and the underwing coverts are white in the northern subspecies and rufous in the southern. Juveniles are very variable. They can be white, buff or rufous below, and sometimes with dark streaks. Their upperparts are browner than in adults, and the thighs are sometimes paler.

Distribution and habitat

The bicolored hawk is widespread but uncommonly observed. Its range extends from Mexico to west Ecuador, the Guianas to Colombia, south to east Peru, through Amazonian Brazil to Paraguay, north-northwestern Argentina,north of Uruguay,Bolivia and to Chile. It mainly resides in forest, along forest edges and in clearings in tropical and locally subtropical zones, although its habitat is none too specialized. It may also reside in rain forest, drier, thinned forest, and palm savanna with gallery forest. Forest disturbance and fragmentation negatively affect the habitat and quantity of the bicolored hawk, which is most abundant in primary undisturbed forest or

riparian forest A riparian forest or riparian woodland is a forested or wooded area of land adjacent to a body of water such as a river, stream, pond, lake, marshland, estuary, canal, Sink (geography), sink, or reservoir. Due to the broad nature of the definitio ...

. There are fewer hawks in disturbed habitats such as forests that have been logged, and even fewer in those fragmented habitats that provide greater than 66% forest cover. These hawks are rarely present in forests that provide less than 66% forest cover.

Behaviour

The bicolored hawk is difficult to detect due to its shyness and inconspicuousness. Because of this behaviour, the bicolored hawk may be more common than it seems.gavião-bombachinha-grande (Accipiter bicolor) , WikiAves – A Enciclopédia das Aves do Brasil
WikiAves (2009-07-11). Retrieved on 2013-04-03.

Vocalisations

Its vocalisations are mainly subdued and unnoticeable. Males have been heard to give a soft, clear whistle and females can emit a loud "''cac cac cac''" when around the nest and young. A barking "''kra-kra-kra-kr-kr-kr-ka''" may also be heard from both sexes. During incubation, males give a sharp "''kek''" vocalisation upon arrival to the nest with food, to which the female replies with a nasal "''wreh''".

Food and feeding

These hawks capture prey in a stealthy manner by flying through dense vegetation to ambush unsuspecting prey. They may also capture prey through aerial pursuit after inconspicuously sitting and watching their target. At times, the bicoloured hawk may hunt in pairs. Most commonly, it feeds on smaller birds such as thrushes,

mockingbird Mockingbirds are a group of New World passerine birds from the family (biology), family Mimidae. They are best known for the habit of some species Mimicry, mimicking the songs of other birds and the sounds of insects and amphibians, often loudly ...

s and small doves, but has also been known to consume small mammals, including bats, as well as reptiles and large insects. Southern race individuals (or females) are also known to take Chilean pigeons. Several instances where the hawks attack groups of squirrel monkeys or

tamarins The tamarins are squirrel-sized New World monkeys from the family (biology), family Callitrichidae in the genus ''Saguinus''. They are the first offshoot in the Callitrichidae tree, and therefore are the sister group of a clade formed by the l ...

have been witnessed. In addition, these hawks may follow groups of monkeys in order to feed on the insects that are exposed by the monkeys.

Breeding

Bicolored hawks breed in forest areas, choosing to build nests on tree branches and occasionally hanging vines. The nest is built in cooperation between the male and female and is constructed from dried sticks and leaves. Each breeding pair will normally build a new nest at the beginning of each breeding year. Copulation occurs after breeding activities such as feeding and nest building have been completed. Egg laying takes place approximately five weeks after copulation and the dull white eggs measure an average of 47.1 mm × 36.5 mm; clutches average 1–3 eggs. The eggs are brooded for about three weeks by the female while the male forages for food. Bicolored hawk chicks are categorized as semi-altricial; the eyes are open at hatching but the chicks are not immediately mobile and are fed by the parents.Parental Care
People.eku.edu. Retrieved on 2013-04-03. The young

fledge Fledging is the stage in a flying animal's life between egg, hatching or birth and becoming capable of flight. This term is most frequently applied to birds, but is also used for bats. For altricial birds, those that spend more time in vulnera ...

around 30–36 days after hatching and the fledgling period spans nearly seven weeks, during which the young will return to the nest frequently for food until they become independent.