Birds eat bones and bathe in iron

Bearded vulture (A bearded eagle) is about 100 – 115 cm tall with a wingspan of 2.5 – 2.85 m, equivalent to the size of some large birds of prey in North America. They have an impressive appearance with an ivory white head and sharp eyes with striking orange-red edges. Their sharp eyes are further highlighted by a strip of jet black fur extending down their beak, like a bandit’s mask. Under the beak is a jagged tuft of feathers, which gives them their name bearded vultures.

As adults, bearded vultures mainly have dark gray and ivory white feathers. However, the hair on the head, chest and legs is often tinged with a rusty orange color due to the habit of bathing in iron-rich mud and sulfur springs.

According to the National Audubon Society, an American environmental non-profit organization, there are two explanations for the bearded vultures’ red bathing behavior. The first is to demonstrate ability. Iron-rich streams are hidden in the middle of the mountains, so only the best can find them, thereby showing off their bravery to mates and rivals. A second explanation is that iron oxide helps fight bacteria, which are common in the carrion they like to eat.

Previously, bearded vultures were widely distributed in many mountain ranges in Africa, Europe and Asia. In Europe, their habitat once ranged across the southern mountain ranges of the continent, from western Spain through the Alps to the Balkans. But currently, their habitat in Europe only remains in a few small areas in the Pyrenees range and the Sierra Nevada range in Spain, the Alps. Small populations of bearded vultures also live on the Mediterranean islands of Corsica and Crete. They are occasionally spotted in Western Europe, including the UK, although very rarely.

Bearded vultures are also called Lammergeier, meaning “sheep vulture” in German, because they often catch sheep. They are scavengers that mainly target medium-sized ungulates such as sheep, goats, and ibex. However, meat is not their favorite food.

The bearded vulture is the only bird in the world that mainly eats bones, accounting for 85 – 90% of its diet. Their large, strong claws are well adapted for breaking bones and extracting nutrients from the marrow inside. Bearded vultures also have stomachs containing extremely strong acid to digest bones. If the bone is too big to swallow, they will fly high and drop the bone on a rocky place to break it into bite-sized pieces. For this reason they are called “quebrantahuesos” in Spanish, meaning “bone breakers”.