Avvoltoio dal groppone bianco

Identificazione

The white-rumped vulture is a typical, medium-sized vulture, with an unfeathered head and neck, very broad wings, and short tail feathers. It is much smaller than the Eurasian Griffon. It has a white neck ruff. The adult's whitish back, rump, and underwing coverts contrast with the otherwise dark plumage. The body is black and the secondaries are silvery grey. The head is tinged in pink and bill is silvery with dark ceres. The nostril openings are slit-like. Juveniles are largely dark and take about four or five years to acquire the adult plumage. In flight, the adults show a dark leading edge of the wing and has a white wing-lining on the underside. The undertail coverts are black.<p>It is the smallest of the Gyps vultures, but is still a very large bird. It weighs 3.5–7.5 kg (7.7–16.5 lb), measures 75–93 cm (30–37 in) in length, and has a wingspan of 1.92–2.6 m (6.3–8.5 ft).<p>This vulture builds its nest on tall trees often near human habitations in northern and central India, Pakistan, Nepal, Bangladesh and southeast Asia, laying one egg. Birds form roost colonies. The population is mostly resident.<p>Like other vultures it is a scavenger, feeding mostly on carcasses, which it finds by soaring high in thermals and spotting other scavengers. A 19th century experimenter who hid a carcass of dog in a sack in a tree considered it capable of finding carrion by smell. It often flies and sits in flocks. At one time, it was the most numerous vulture in India.<p>Within the well-supported clade of the genus Gyps which includes Asian, African, and European populations, it has been determined that this species is basal with the other species being more recent in their species divergence.

Tassonomia

The white-rumped vulture was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the vultures in the genus Vultur and coined the binomial name Vultur bengalensis.Gmelin based his description on the "Bengal vulture" that had been described and illustrated in 1781 by the English ornithologist John Latham in his multi-volume A General Synopsis of Birds. Latham had seen a live bird at the Tower of London and had been told by the keeper that it had come from Bengal. The white-rumped vulture is now one of eight species placed in the genus Gyps that was introduced in 1809 by the French zoologist Marie Jules César Savigny. The genus name is from Ancient Greek gups meaning "vultur". The species is monotypic: no subspecies are recognised.

Nome scientifico

Gyps bengalensis

Autorità

(Gmelin, JF, 1788)

Ordine

Accipitriformi

Famiglia

Accipitridae

Genere

Gyps

Areale e habitat

Migrazione

Nomadic movement

Comportamento

White-rumped vultures usually become active when the morning sun is warming up the air so that thermals are sufficient to support their soaring. They were once visible above Calcutta in large numbers.<p>When they find a carcass, they quickly descend and feed voraciously. They perch on trees nearby and are known to sometimes descend also after dark to feed. At kill sites, they are dominated by red-headed vultures Sarcogyps calvus.In forests, their soaring often indicated a tiger kill. They swallow pieces of old, dry bones such as ribs and of skull pieces from small mammals.Where water is available they bathe regularly and also drink water. A pack of vultures was observed to have cleaned up a whole bullock in about 20 minutes. Trees on which they regularly roost are often white from their excreta, and this acidity often kills the trees. This made them less welcome in orchards and plantations.<p>They sometimes feed on dead vultures. One white-rumped vulture was observed when getting caught in the mouth of a dying calf.Jungle crows have been sighted to steal food brought by adults and regurgitated to young.<p>Allan Octavian Hume observed "hundreds of nests" and noted that white-rumped vultures used to nest on large trees near habitations even when there were convenient cliffs in the vicinity. The preferred nesting trees were Banyan, Peepul, Arjun, and Neem. The main nesting period was November to March with eggs being laid mainly in January. Several pairs nest in the vicinity of each other and isolated nests tend to be those of younger birds. Nests are lined with green leaves.In Mudumalai Tiger Reserve, white-rumped vultures used foremost Terminalia arjuna and Spondias mangifera trees for nesting at a mean height of 26.73 m (87.7 ft). Their nests were 1 m (3 ft 3 in) long, 40 cm (16 in) wide and 15 cm (5.9 in) deep. Hatchlings were seen from the first to the second week of January.<p>Solitary nests are not used regularly and are sometimes taken over by the red-headed vulture and large owls such as Bubo coromandus. The male initially brings twigs and arranges them to form the nest. During courtship the male bills the female's head, back and neck. The female invites copulation, and the male mounts and hold the head of the female in his bill. Usually, the female lays a single egg, which is white with a tinge of bluish-green. Female birds destroy the nest on loss of an egg. They are usually silent but make hissing and roaring sounds at the nest or when jostling for food. The eggs hatch after about 30 to 35 days of incubation. The young chick is covered with grey down. The parents feed them with bits of meat from a carcass. The young birds remain for about three months in the nest.<p>Mycoplasmas have been isolated from tissues of a white-rumped vulture. Mallophagan parasites such as Falcolipeurus and Colpocephalum turbinatumhave been collected from the species.Ticks, Argas (Persicargas) abdussalami, have been collected in numbers from the roost trees of these vultures in Pakistan.<p>A captive individual lived for at least 12 years.

Conservazione

Currently, only the Cambodia and Burma populations are thought to be viable though those populations are still very small (low hundreds). It has been suggested that the use of meloxicam (another NSAID) as a veterinary substitute that is safer for vultures would help in the recovery. Campaigns to ban the use of diclofenac in veterinary practice have been underway in several South Asian countries.<p>Conservation measures have included reintroduction, captive-breeding programs and artificial feeding or "vulture restaurants". Two chicks, which were apparently the first captive-bred white-rumped vultures ever, hatched in January 2007, at a facility at Pinjore. However, they died after a few weeks, apparently because their parents were an inexperienced couple breeding for the first time in their lives – a fairly common occurrence in birds of prey.

Tendenza della popolazione

declining