Yesterday on our Facebook group, a member asked for an ID of a huge bird of prey he had seen circling over the Peak District. Despite some missing feathers and a damaged tail it was quickly identified as a bearded vulture, which had first been spotted in the UK a couple of weeks earlier on the 26th June in Kenilworth by Lucy Burrell who reported her sighting to BirdGuides.
Bearded vultures, also known as lammergeiers, are sparsely distributed over a wide range from the Himalayas to the Ethiopian Highlands. In Europe they are found in the Pyrenees and the Alps which provide the canyons, cliffs, and crevices they like to call home.
They are massive – veritable flying barn doors – weighing up to 7 kg and with a wingspan of almost 3 metres. Compare this with the golden eagle which has a wingspan of anything from 1.8 to 2.3 metres, or even the UK’s largest bird of prey, the white-tailed eagle, which has a wingspan of up to 2.4 metres.
Adult bearded vultures have black wings and tails and bright rust-coloured underparts due to rubbing themselves against ferric oxide particles whilst dust-bathing, or from drinking mineral-rich water. They have relatively small heads and unlike most vultures which are bald bearded vultures have reddish or white plumage on their crowns and a distinctive black ‘beard’ of feathers underneath their bills.
It is thought that the orange colour doesn’t have any practical purpose and is merely a status symbol. Scientists have observed that the intensity of the colour directly correlates to a bird’s age and size so bearded vultures with the brightest feathers have had the time and resources to find suitable places to bathe.
Captive birds also rub their feathers to colour them which suggests the behaviour is instinctive, rather than learned.
<h2Bone breakers
The bearded vulture spotted in the UK is a juvenile approximately two years old. Younger birds look quite different from adults with paler, buff underparts, taking about 7 years to reach full adult plumage.
The missing tail feathers meant that the distinctive lozenge-shaped tail which is unusual in birds of prey was not obvious but also meant that this bird was recognisable as the same bird that had been spotted over the Channel Islands on the 20th May, The Netherlands near the German border on the 30th May, and Belgium on the 18th June.
After the first sighting in the UK it made its way north spending some time in Derbyshire and Yorkshire before arriving in the Peak District where it is making regular use of a roosting site in the north of the Peak District National Park.
The rocky ridges and gritstone cliffs mimic its European homeland and the area has a plentiful supply of sheep carcasses on which bearded vultures prefer to feed. Lammergeier originates from a German word for ‘lamb vulture’ but despite its reputation and the fears of some local residents bearded vultures don’t often take live prey.
In fact, they tend to ignore the actual meat on a carcass and live on a diet that is about 90% bone marrow, the only species of bird known to do so. Bearded vultures have a long, narrow tongue covered in grooves which they use to scrape out the marrow from a bone. If they are unable to get at all the marrow they will bite through or swallow whole bones as large as 25 cm long and 3.5 cm wide.
To prevent damage from swallowing bones bearded vultures have an thick, elastic oesophagus which can stretch to accommodate the pieces of jagged bone. It also lacks a crop, used by most bird species to store food, where splinters of bone could get stuck, causing internal injuries.
Larger bones are carried to a height of 150 m above the ground from where they are dropped onto areas of flat rock to break them into smaller pieces. If the bones don’t shatter on the first attempt the bearded vulture will repeat the process several times. The skill requires extensive practice and can take up to 7 years to perfect. This habit gave rise to the bearded vulture’s old name ossifrage which comes from the Latin for ‘bone-breaker’.
On occasion bearded vultures have been observed trying to break bones by hammering them into rocks while perched. They will also drop tortoises from a great height to crack open their shells to get at the meat inside, and golden eagles have been observed despatching of tortoises in the same way.
The almost exclusive bone marrow diet of the bearded vulture means it doesn’t have to compete with other vultures and animals for the carcass. Skeletons dehydrate which protects them from bacterial degradation and bones can be consumed months after the soft parts of a carcass have been eaten by other animals, larvae, and bacteria.
The stomach acid of a bearded vulture is estimated to have a pH of about 1 which means large bones can be digested in about 24 hours. The high fat content of bone marrow makes the net energy value of bone almost as good as that of muscle even if the bone is not fully digested.
It is not yet known where in Europe the bearded vulture originated from. A reintroduction programme has been taking place in the Alps since the 1980s where young bearded vultures brought up in captivity have been released into the wild. As the bearded vulture spotted in the Peak District has no ring or tracking tag it is not a released bird but was born in the wild, either in the Alps or the Pyrenees.
If it was born in the Pyrenees it would be treated as a wild bird and therefore eligible to be placed in Category A on the Official British List as a rare vagrant. However, if it is an Alpine bird it will be classed as a reintroduction and would only be included in Category E for record keeping. This is because the breeding population in the Alps is not yet thought to be self-sustaining.
This is not the first time a bearded vulture has flown into the UK. In 2016 a specimen was spotted in the West Country and Wales – this bird also originated from the Alps and was placed in Category E. Although bearded vultures have vast ranges it is unusual for them to cross large bodies of water so why it made its way across the English Channel is puzzling.
As long as it is able to find food and a safe roosting site the bearded vulture will have no reason to leave the UK. If it decides to leave, the return to the Alps or the Pyrenees is a potentially hazardous journey and sometimes these long-distance vagrants need to be rescued and assisted to get back home. Another concern for now is that the bearded vulture is in an area known for raptor persecution.
If you decide that you want to go and have a look for this magnificent bird then ensure that you do nothing to disturb it and observe it from a safe distance.
