Bearded Vulture, bones and the importance of calcium

Over the last week Britain’s first ever recorded bearded vulture (lammergeier) was seen in Gwent and then on Dartmoor. It seems likely it was the young vulture seen in Belgium on 9th May and thought to be a wild bird from the mainland European population, which is increasing. It must have had a shock in our country because its natural food is large dead mammals and our farm regulations now insist on all dead livestock being cleaned up from the countryside. A bit like us going to the supermarket and finding all the shelves empty. The bearded vulture is the last species in the chain of vultures which eat and clean up large animal carcasses. After the griffons and black vultures have feasted on the carrion, the bearded vulture is the ultimate scavenger by breaking the large bones and eating the marrow. Nowadays in our sanitised countryside there’s not much opportunity for bearded vultures, nor burying beetles or bone fungi.

In fact the removal of calcium, in the form of bones, from the countryside is a major change in the last hundred years. This is particularly problematic in the uplands where calcium is scarce, and the annual loss in the form of sheep and cattle bones is massive, as stock go to market. It must be thousands of tons per year, and nowadays even the bones of most red deer are carried off the hills. But is this loss of calcium a problem for the ecosystem? I learnt recently that a scientist had shown that the eggs of the ring ouzel, the mountain blackbird, had become thinner and thus more vulnerable, probably because of acid rain causing losses of calcium in the uplands. I’m not suggesting female ring ouzels could eat bones, before laying their eggs, but there’s no doubt that any bone or deer antler left in the countryside is quickly gnawed by creatures seeking calcium.   It’s all part of the web of life in which we live.

My personal view is that no calcium should be removed from nature reserves and protected areas, so that the carcasses of culled deer are left in situ. This would be a major contribution to carrion eaters whether invertebrates, birds or mammals, and then for fertilising plants or hosting fungi. This may run counter to our fixation on health and cleanliness, and I’m also told by my reserve manager friends that it would cause a problem by increasing the numbers of foxes and badgers. But that leads on to another issue about large functioning ecosystems, where high numbers of middle-guild predators require control from the return of lynx and wolf. It’s interesting where thinking about a lost bearded vulture takes us – I just hope it finds a big dead animal in Dartmoor National Park. Or for goodness someone put out a couple dead horses! You never know it could become the first step in vulture recolonisation of Britain.