Bearded Vulture - Behaviour

Behaviour

Like other vultures it is a scavenger, feeding mostly on animal matter from dead animals. It usually disdains the actual meat, however, and lives on a diet that is 85-90% bone marrow. The Lammergeier 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 Lammergeier 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. After dropping the large bones, the Bearded Vulture spirals or glides to 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 seldomly, 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.

Live prey is sometimes attacked by the Bearded Vulture, with perhaps greater regularity than any other vulture. Among these, especially tortoises are targeted depending on their local abundance. Tortoises predated may be nearly as large as the predating 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, been observed to be predaceously 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 precipitious 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 have appeared sickly or are obviously injured. Humans have been anecdotedly reported to have been killed in the same way, although this (if it does happen) is generally agreed to be accidental on the part of the vulture. Occasionally smaller ground-dwelling birds, such as partridges and pigeons, have been reported to eaten, sometimes as fresh carrion and sometimes 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 ft) high. Occasionally, breeding pairs may forage and hunt together. In the Ethiopian Highlands only, Bearded Vultures have adapted to living largely off of human refuse.