Bearded vulture

Name and taxonomy

Carl Linnaeus described the bird in 1758 and placed it in the genus Vultur. He worked from a picture George Edwards made in 1750. Edwards drew a specimen collected near Oran in Algeria. Gottlieb Storr set up the genus Gypaetus in 1784, and the species has held it alone ever since. Gypaetus comes from a Greek word for an eagle or a vulture. Barbatus is Latin for bearded.

Lammergeier comes from the German for lamb-vulture. The name records an old belief that the bird carries off lambs. Ossifrage comes from a Latin word meaning bone-breaker. The same root gave English the word osprey. Two subspecies are accepted today, out of five that people have proposed. The African form is smaller and lacks the black ear tuft and the chin bristles.

Evolution and relatives

The bearded vulture is not a true Old World vulture. It forms a small branch of the family Accipitridae with the Egyptian vulture. That bird is its closest living relative. It stands no closer to the other Old World vultures than a hawk does.

The feathered neck is the clearest difference from those birds. Both this bird and the Egyptian vulture carry a lozenge-shaped tail, which is odd in a bird of prey. The whole shape has been compared to a falcon built at enormous size. The bone diet is unique among living birds, so it is probably a late specialisation.

Appearance

An adult is grey-blue to grey-black across the back. The forehead is cream, and a black band crosses the eyes. Black bristles hang under the chin as a beard. Head, breast and leg feathers are often orange or rust. That colour is not pigment in the feather. The bird works iron-rich mud into its plumage, and some of it rubs off onto the eggs.

The wings are long and narrow, and the wing chord runs 71.5 to 91 centimetres. The tail is wedge-shaped and measures 42.7 to 52 cm. It is longer than the wing is wide, which is unusual. The legs are short for the size of the bird, with a tarsus of 8.8 to 10 cm. The feet are large and powerful, and the walk on the ground is a waddle.

A young bird is dark black-brown, with a grey-brown breast. It gains adult plumage over several years. Full maturity takes five to seven years, and first breeding comes at eight or later. Females are a little larger than males. Birds around the Himalayas run slightly larger than birds from other ranges.

Habitat and range

The bird is spread thinly over an enormous range. It breeds in the Pyrenees, the Alps, the Caucasus, the Zagros, the Altai and the Himalayas. It also holds ground in Arabia, Afghanistan, Ladakh and western China. In Africa it lives in the Atlas Mountains and the Ethiopian Highlands. It runs south from Sudan to central Kenya and northern Tanzania. An isolated group holds the Drakensberg in South Africa.

The bird keeps to the tree line and above it. It is rare below 1,000 metres and usually stays above 2,000 metres. It reaches 4,500 metres in Africa and 5,000 metres in central Asia. One bird was recorded living at 7,500 metres in the Himalayas. Another was watched flying at 7,300 metres. In southern Armenia it will nest below 1,000 metres where cliffs allow.

Cliffs probably matter more to this bird than any particular plant cover. In Ethiopia it is common at rubbish tips outside small towns. The species is recorded in 67 countries on GBIF. Wandering birds from the Alps release schemes have reached Britain and Sweden. Those birds count as escapes rather than wild vagrants.

Diet and hunting

Bone is the whole trade of this bird. Mammals give 93 percent of the diet, birds 6 percent and reptiles 1 percent. Medium-sized hoofed animals supply most of that. The bird usually leaves the meat, and 85 to 90 percent of its food is bone and marrow. It swallows a bone up to the size of a lamb's thigh bone whole. Fatty, elongated bones are preferred, because they hold the most marrow.

A bone too large to swallow gets carried up 50 to 150 metres and dropped onto rock. The bird spirals down to check the pieces, and drops the bone again if it held together. It can carry a bone 10 centimetres thick that weighs over 4 kilograms. That load is close to the weight of the bird itself. Young birds need up to seven years of practice to learn the skill. Some birds hammer a bone against rock from a perch instead.

The stomach runs at about pH 1 and dissolves a large bone in about 24 hours. Dry bone is better food than it looks. About 140 grams of it hold the protein of 111 grams of muscle. By weight, fresh bone carries about 108 percent of the energy that fresh meat holds. A skeleton left on a mountain dries out and resists bacteria. The vulture can return months later and still make a meal of it.

This bird also kills, more often than most vultures do. Tortoises are the favourite target, and it drops them on rock like a bone. Hyraxes, hares and marmots have all been taken, and once a monitor lizard 62 centimetres long. Ibex, chamois and wild goats have been battered with the wings until they fell from a ledge. Most of those victims were young, sick or already hurt. The bird searches low, at 2 to 4 metres above the rock.

Behaviour and social life

The bearded vulture is solitary for most of the year. A pair holds an enormous territory and may forage over 2 square kilometres in a day. The bond between the two birds is close all the same. They sometimes hunt and forage together.

Display flights involve tumbling, spiralling and showing the talons. Two birds will lock feet and fall together through the sky. The bird bathes in dust and mud rather than in water. It carries food to the nest in its feet, unlike vultures that feed young by regurgitation. In the Ethiopian Highlands it now lives largely off human refuse.

Communication and senses

The bearded vulture has very little to say. Adults are silent for most of the year. A shrill whistle belongs to the breeding display. Near the nest the birds make a falcon-like call, written as cheek-acheek.

Most of the message goes by sight instead. A display flight probably shows the talons and the size of the bird at once. Locked feet and a shared fall probably serve both pairing and territory. Sight leads the search for food, and the bird flies low over rock to find it. It arrives late at a carcass, when the soft parts have gone.

Reproduction and life cycle

The breeding season varies from region to region. It runs December to September in Eurasia and November to June in the Indian subcontinent. In Ethiopia it runs October to May, and in eastern Africa it never stops. In southern Africa it runs May to January. Pairs are monogamous, and both birds care for the young. Polyandry has been recorded a few times.

The nest is a heap of sticks on a ledge, an outcrop or inside a cave. A new nest is about 1 metre across and 69 centimetres deep. After repeated use it grows to 2.5 metres across and 1 metre deep. Layers of animal remains from meals build up inside it. A cliff site keeps nest-robbing mammals out. One Spanish nest held shoes dated between the 13th and the 19th centuries.

A female lays one or two eggs, and three have been recorded on rare occasions. Incubation lasts 53 to 60 days, and the eggs hatch at the start of spring. The chicks stay in the nest for 100 to 130 days. A chick eats more meat and skin than an adult does. A young bird may depend on its parents for two years, so many pairs breed in alternate years.

A wild bearded vulture lives about 21.4 years on average. Captive birds have reached at least 45 years. Females first breed at about 7.7 years and males at about 8.9. A pair fledges about 0.43 young a year.

Predators and threats

An adult has no natural predator. People are the whole problem. Hunting and poisoning wiped the bird out of central Europe during the 20th century. Shooting went on in the Alps until 1913. The last Carpathian birds were shot in 1927. Israel lost its breeding birds in 1981.

Poison put out for carnivores still kills vultures. Power lines kill birds by collision. Roads and houses take away nesting ground. Less food is available where livestock has left the high pastures. Trophy hunting continues in some places. Low genetic diversity and inbreeding are worst in the southern African birds.

Population and conservation

The IUCN listed the species as Least Concern in 2004 and moved it to Near Threatened in 2014. It is one of the most endangered birds in Europe. Densities are naturally low, from a dozen to 500 pairs in a mountain range. Ethiopia holds the most, with an estimated 1,400 to 2,200 pairs. Southern Africa held about 632 birds in 2010. Naturalists have logged 7,930 records on iNaturalist.

Spain fell to 30 birds by the end of the 20th century. A foundation set up there in 1995 has brought the national total above 1,000. Reintroduction in the Alps began in the 1970s with birds caught in Afghanistan. That attempt failed, because the birds were hard to catch and many died in transport. A second scheme from 1987 placed young zoo birds on protected cliffs and hand-fed them. Over 200 birds went out in the Alps between 1987 and 2015, and the population has held.

Relationship with humans

The bird cleans bone off the mountain, and no other animal does that work. Farmers once believed it carried lambs away, and the German name still says so. It does not take healthy livestock. It does take carrion near villages, and Ethiopian birds work the rubbish tips. Feeding stations now support several populations.

Conservation plans target poison, power lines and persecution. South Africa has a national management plan for the species. Outreach work tries to cut the number of poisoning incidents. Zoos hold the breeding stock that supplies the release schemes. Like other large raptors, it makes an impossible pet and the law protects it.

In culture and myth

In Iranian tradition the bird is the Homa, a sign of luck and happiness. The story says the shadow of a Homa falling on a person foretells a crown. It also says that anyone who shoots the bird will die within forty days. Sufi poetry treats the Homa as a goal nobody can catch. In Mughal India a Homa that landed on someone was read as a promise of kingship.

Sa'di noted the bone diet in the Gulistan, written in 1258. Emperor Jahangir had a bird's crop opened in 1625 and found it full of bones. Greek soothsayers counted the ossifrage among the few birds that could give a valid sign. Aeschylus is said to have died when an eagle dropped a tortoise on his bald head. If that story is true, this bird is the likely culprit.

In Tibet the dead are given to vultures in a rite called sky burial. Prayers and mantras go with the rite, and the birds themselves are blessed. Tibetan calls the bird jagod. In Leviticus the ossifrage is on the list of birds that may not be eaten. Shimon Persky found a nest of these birds in the Negev in 1944. The Hebrew name is peres, and he took it as his surname.