White hawk
The white hawk ("Pseudastur albicollis") is a bird of prey breeding in the tropical New World of the family Accipitridae. Though it is commonly placed in the subfamily Buteoninae, the validity of this group is doubtful and currently under review. Description. The adult white hawk ranges from 46–56 cm (18–22 in) long with very broad wings and has a white head, body and underwings. The upper wings are black, and the very short tail is black with a broad white band. The bill is black and the legs are yellow. The sexes are similar, but females are larger  and heavier—840 g (1.85 lb) compared to the male's 650 g (1.43 lb). Immature birds have extensive black spotting on the upperparts and dark-streaked whitish underparts. The call of the white hawk is a plaintive "kerwee". Subspecies. There are four subspecies: All subspecies look mainly white from below. The identity of the birds discovered in 2000/2001 in the Serranía de las Quinchas of central Colombia  is unclear. Systematics. The white hawk was described by John Latham: in English (1787) as the "white-necked falcon", and in Latin (1790) as "Falco albicollis", with locality "Cayenne". Around 1850, Edward Blyth  created the genus "Pseudaster", with ""Falco pæcilonotus" Cuvier" as the type and ""F.skotopterus" Pr. Max." as a synonym. In his "Genera of Birds", Gray treats them both as "Buteo"s, listing "B. albicollis" in the main text and "B. pæcilonotus" in the index. Peters' influential 1931 checklist placed the white hawk in Kaup's genus "Leucopternis", listing five subspecies: "L. albicollis albicollis", "L. a. ghiesbrechti", "L. a. costaricensis", "L. a. occidentalis", and "L. a. polionota". During the 20th century, some authors treated the grey-backed hawk "occidentalis" as a subspecies of "L. albicollis", whilst others recognized it as a separate species . In the first decade of the 2000s "Leucopternis" was found to be polyphyletic, and in 2012 the American Ornithologists' Union separated the white hawk and its relatives under the old name "Pseudaster". DNA analysis found that the subspecies "P. a. albicollis" is sister to "P. a. polionotus", and the trans-Andean "P. a. ghiesbreghti" and "P. a. costaricensis" are more closely related to "P. occidentalis" than they are to "P. a. albicollis". Distribution and ecology. This is a bird of lowland forest and other woodlands. It ranges from southern Mexico through Central and South America to Peru, Bolivia and Brazil . It also breeds on Trinidad. The white hawk's range in central South America is the entire Amazon basin, from the Andes on the west to the Guianas on the Atlantic on the northeast, and to the transition lands to the south. A widespread species, it is usually not common, but the IUCN considers it not to be globally threatened due to the large extent of its range. The white hawk feeds mainly on reptiles with some insects and mammals, caught in a sortie from a perch. It associates with foraging groups of tufted capuchin monkeys ("Cebus apella") and South  American coatis ("Nasua nasua") to snatch prey startled by these animals. This species is often seen soaring, and has a spectacular aerial courtship display. It builds a large stick platform nest in a tree and usually lays one dark-blotched blue-white egg. An attended nest was observed in Ecuador in mid-August.