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Bearded vulture

Like other vultures it is a scavenger, feeding mostly on the remains of dead animals. It usually disdains the actual meat, however, and lives on a diet that is typically 85–90% bone marrow. This is the only living bird species that specializes in feeding on marrow. The bearded vulture can swallow whole or bite through brittle bones up to the size of a lamb's femur and its powerful digestive system quickly dissolves even large pieces. The bearded vulture has learned to crack bones too large to be swallowed by carrying them in flight to a height of 50–150 m (160–490 ft) above the ground and then dropping them onto rocks below, which smashes them into smaller pieces and exposes the nutritious marrow.They can fly with bones up to 10 cm (3.9 in) in diameter and weighing over 4 kg (8.8 lb), or nearly equal to their own weight.[8] After dropping the large bones, the bearded vulture spirals or glides down to inspect them and may repeat the act if the bone is not sufficiently cracked. This learned skill requires extensive practice by immature birds and takes up to seven years to master. Its old name of ossifrage ("bone breaker") relates to this habit. More seldom, these birds have been observed to try to break bones (usually of a medium size) by hammering them with their bill directly into rocks while perched. During the breeding season they feed mainly on carrion. They prefer limbs of sheep and other small mammals and they carry the food to the nest unlike other vultures which feed their young by regurgitation.

 

Live prey is sometimes attacked by the bearded vulture, with perhaps greater regularity than any other vulture. Among these, tortoises seem to be especially favored depending on their local abundance. Tortoises preyed on may be nearly as heavy as the preying vulture. When killing tortoise, bearded vultures also fly to some height and drop them to crack open the bulky reptiles' hard shells. Golden eagles have been observed to kill tortoises in the same way. Other live animals, up to nearly their own size, have been observed to be predaciously seized and dropped in flight. Among these are rock hyraxes, hares, marmots and, in one case, a 62 cm (24 in) long monitor lizard. Larger animals have been known to be attacked by bearded vultures, including ibex, Capra goats, Chamois and Steenbok. These animals have been killed by being surprised by the large birds and battered with wings until they fall off precipitous rocky edges to their deaths; although in some cases these may be accidental killings when both the vulture and the mammal surprise each other. Many large animals killed by bearded vultures are unsteady young, or have appeared sickly or obviously injured. Humans have been anecdotally reported to have been killed in the same way. However, this is unconfirmed and, if it does happen, most biologists who have studied the birds generally agreed it would be accidental on the part of the vulture. Occasionally smaller ground-dwelling birds, such as partridges and pigeons, have been reported eaten, possibly either as fresh carrion (which is usually ignored by these birds) or killed with beating wings by the vulture. While foraging for bones or live prey while in flight, bearded vultures fly fairly low over the rocky ground, staying around 2 to 4 m (6.6 to 13.1 ft) high. Occasionally, breeding pairs may forage and hunt together. In the Ethiopian Highlands, bearded vultures have adapted to living largely off human refuse.

 

Breeding

 

The bearded vulture occupies an enormous territory year-around. It may forage over two square kilometers each day. The breeding period is variable, being December through September in Eurasia, November to June in the Indian subcontinent, October to May in Ethiopia, throughout the year in eastern Africa and May to January in southern Africa. Although generally solitary, the bond between a breeding pair is often considerably close. In a few cases, polyandry has been recorded in the species. The territorial and breeding display between bearded vultures is often spectacular, involving the showing of talons, tumbling and spiralling while in solo flight. The large birds also regularly lock feet with each other and fall some distance through the sky with each other. The nest is a massive pile of sticks, that goes from around 1 m (3.3 ft) across and 69 cm (27 in) deep when first constructed up to 2.5 m (8.2 ft) across and 1 m (3.3 ft) deep, with a covering of various animal matter from food, after repeated uses. The female usually lays a clutch of 1 to 2 eggs, though 3 have been recorded on rare occasions. which are incubated for 53 to 60 days. After hatching the young spend 100 to 130 days in the nest before fledging. The young may be dependent on the parents for up to 2 years, forcing the parents to nest in alternate years on a regular basis. Typically, the bearded vulture nests in caves and on ledges and rock outcrops or caves on steep rock walls, so are very difficult for nest-predating mammals to access. Wild bearded vultures have a mean lifespan of 21.4 years, but have been observed to live for up to at least 45 years in captivity.

 

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Uploaded on August 21, 2017
Taken on April 9, 2017