Topic : Rare Birds
Article 46 25 June 2008
The Montane Bone-bird!
The Bearded vulture Gypaetus barbatus or Lammergeier as it used to be called, is the only bird in the world that can survive almost exclusively on a bone diet.
About 70 – 80 percent of what it consumes is bone and bone marrow that it scavenges from carcasses. With highly acidic digestive juices (pH ca 1.0 – 1.5), they are well adapted to processing bone that begins to dissolve the moment it reach their stomach. Meat and skin is also fed on, but this probably only makes up about 20 - 25 percent of what they eat.
The bulk of their diet comes from sheep and goat carcasses, and also from medium sized ungulates. They are particularly partial to leg bones. Smaller bones and bone chips are swallowed immediately, while larger bones are carried into the air and dropped onto a flat favourite rocky area known as an ‘ossuary’ until broken. The bird then spirals down to consume the broken pieces and to get at the bone marrow.
Bearded Vultures are found only in the alpine and mountainous regions in central Europe, Asia and Africa. The small isolated population in southern Africa is centered on the Lesotho highland region but birds may wander from there to surrounding grassland regions in search of carcasses.
Their large wedge-shaped tail is the key ID feature when souring high in the sky. Juvenile and immature birds have very different plumages to that of the adults. They are overall darker and more shaggy looking.
The imm brown plumage is retained till birds are about 6 yrs old. Although Bearded Vultures are not threatened globally, they are regarded as Red Data species in South Africa, listed as Endangered with the main threat to the relatively small population being poisoning.