Greater Yellow-headed Vulture (Cathartes melambrotus)

[order] FALCONIFORMES | [family] Cathartidae | [latin] Cathartes melambrotus | [authority] Wetmore, 1964 | [UK] Greater Yellow-headed Vulture | [FR] Grand Urubu | [DE] Grosser Gelbkopfgeier | [ES] Aura Selvatica | [NL] Grote Geelkopgier

Subspecies

Genus

Physical charateristics

The adult is a very deep black overall, with green and purple sheen. Its eyes are red, its feet black and its beak id flesh coloured. The throat and the sides of the head vary from deep yellow to pale orange, with a blue crown and a blue spot in front of the eyes.

Range

South America : Amazonia

Habitat

Typically low tropical forest and less inclined to use open or disturbed forest. 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 urohydrosis, in which it urinates or defecates on its legs to cool them evaporatively. This behavior is exhibited by storks and New World vultures.

Reproduction

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; eggs are incuated for about five to seven weeks.

Feeding habits

The primary staple of this vulture’s diet is carrion, though it is very fond of fish, and may occasionally take them alive. Relies heavily on olfactoin (smell) to detect prey. The Greater Yellow-headed Vulture is a scavenger and subsists entirely on carrion. It will eat roadkill or other animal carcasses. It prefers fresh meat, but often cannot make the first cut into the carcass of a larger animal as its beak is not strong enough to tear into the tough hide. After a few days, the Greater Yellow-headed Vulture will no longer feed on a piece of carrion, as the meat will begin to decay and become contaminated with microbial toxins. It will drink water from a pool, pond, or any receptacle provided. Like other vultures, they play an important role in the ecosystem by disposing off carrion which could otherwise be a breeding ground for disease. The Greater Yellow-headed Vulture forages using its keen eyesight to locate carrion on the ground, but also uses its sense of smell, an ability which is uncommon in the avian world. It locates carrion by detecting the scent of ethyl mercaptan, a gas produced by the beginnings of decay in dead animals. The olfactory lobe of its brain responsible for processing smells is particularly large compared to other animals. This characteristic of New World Vultures has been used by humans: ethyl mercaptan is injected into pipelines, and engineers looking for leaks then follow the vultures. King Vultures, which lack the ability to smell carrion, follow the Greater Yellow-headed Vultures to carcasses, where the King Vulture tears open the skin of the dead animal. This allows the smaller Greater Yellow-headed Vulture access to food, as it does not have a bill strong enough to tear the hide of larger animals. This is an example of mutual dependence between species. It is generally displaced from carcasses by both Turkey Vultures and King Vultures, due to their larger size.

Video Greater Yellow-headed Vulture

httpv://www.youtube.com/watch?v=QTrjd1H-Zao

copyright: J. del Hoyo

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The Greater Yellow-Headed Vulture inhabits savannas, Grasslands, and Marshes in South America. It ranges from Argentina and Urugay, as far north as Mexico. In Surinam widely spread in the interior, much less common in the coastal planes. Identification of species uncertain due to overlapping range with Lesser Yellow-headed Vulture.

Migration

Irruptive or local migrant

Distribution map