Greater Yellow-headed Vulture

The greater yellow-headed vulture is 64–75 centimetres (25–30 in) in length, with a wingspan of 166–178 centimetres (65–70 in), a tail length of 25–29 centimetres (9.8–11.4 in) and a weight averaging 1.65 kilograms (3.6 lb). Its plumage is black with a green or purple sheen. The throat and the sides of the head are featherless. The skin on the head ranges in color from deep yellow to pale orange with a blue crown. The nape and the area near the nostrils are pale pinkish. The undersides of the wings are black, while the flight feathers are a lighter shade. The quills of the eleven primary feathers appear to be white when seen from above. The tail is rounded and long for a vulture, extending to or slightly beyond the tip of the closed wing. The sexes are outwardly similar. The head is dull greyish in juveniles, which otherwise resemble adults. The irises of its eyes are red, its feet are black, and its beak is flesh-colored. The eye has a single incomplete row of eyelashes on the upper lid and two rows on the lower lid. Its beak is thick, rounded, and hooked at the tip. Because of its habit of urohidrosis, the scaly portions of its legs are often streaked white with uric acid. The front toes are long with small webs at their bases and are not adapted to grasping. The opening of the nostril is longitudinal and set in a soft cere, and the nostril lack a septum. …

The greater yellow-headed vulture is found in the Amazon Basin of tropical South America; specifically in south-eastern Colombia, southern and eastern Venezuela, Guyana, French Guiana, Suriname, northern and western Brazil, northern Bolivia, eastern Peru and eastern Ecuador. It is not found in the Andes, in the lowlands west or north of the Andes, in the relatively open regions of northern South America, eastern South America, or in the southern subtropical regions. It has a large range, with an estimated global extent of occurrence of 6,700,000 square kilometers (2,586,884.5 sq mi). Its natural habitat is tropical moist lowland forests. It is not generally found in high-altitude regions. It is common in heavily forested regions. It may wander over grasslands, but rarely strays far from forested areas, which provide shelter and nesting areas.

The greater yellow-headed vulture roosts on high, exposed dead trees to observe surrounding terrain. When flying, it travels in pairs or alone and is rarely found in groups. Flight is heavy and steady. It flies with its wings held flat or very slightly above horizontal, in what is called the dihedral position. The flight of the greater yellow-headed is an example of static soaring flight, which uses thermals to maintain altitude without the need to flap its wings. The greater yellow-headed vulture also has the unusual habit of urohidrosis, in which it urinates or defecates on its legs to cool them evaporatively. This behavior is exhibited by storks and New World vultures.

Breeding. Greater yellow-headed vultures do not build nests, but rather lay their eggs directly on cliffs, the floors of caves, the ground, or in the hollows of stumps. Eggs are cream-colored and blotched with brown spots, particularly around the larger end. Clutch size ranges from one to three, though two is the norm. The chicks are altricial—blind, naked and relatively immobile upon hatching, and grow down feathers later. The parents feed their young by regurgitating pre-digested food into their beak, where the chicks then drink it. Young fledge after two to three months.

Feeding. The greater yellow-headed vulture is a scavenger and subsists entirely on carrion. …