Who and what threatens griffon vultures?
Birds of prey, which are on top of the food chain, accumulate large amounts of pesticides in their tissues. This can result in sterility, thinning of eggshell (due to disorders in calcium metabolism by females), bursting shells, embryo mortality, deviations in the normal behaviour of parents or direct death. An analysis of dead vultures from Kvarner has shown that in the brain of one young vulture traces of mercury, lead and arsenic were found. Where do these traces come from, considering the fact that the bird lived just six months after hatching? The bird lost its balance when flying, crashed into bushes and broke one wing. Three days later it died. What caused this disruption in the balance during the flight?
Interesting fact: At the beginning of the twentieth century vultures began to disappear rapidly from Europe, primarily due to changes in the management of livestock. At the same time, hunters were getting better control over the number of wild animals (game), so there were less sick or old deer, boars and chamois or dead animals, cause of death being natural death, available, and at the same time less and less residuals after wolfs' meals, which meant less food for vultures. Griffon vultures were forced to start eating dead farm animals and animals living on pastures, such as goats and sheep in the Croatian Karst regions.
During World War II, the number of wolves and foxes multiplied and after the war they started to poison them by strychnine. Of course, vultures are not resistant to this synthetic poison, as well as to other poisons, as cyanide and organochlorides, which are used in agriculture as pesticides to protect plants and crops from insects and disease. In 1950s over 40 vultures were found dead in Macedonia, because they ate dead sheep, poisoned by strychnine, intended as wolf bait for their destruction. In late 1980s again 10 dead vultures were found in the same area. Some people used also other types of poison instead of strychnine. At that time it was possible to buy an infinite quantity of pesticides in every agricultural pharmacy. So in Blagaj near Mostar, one shepherd filled a sheep with liquid pesticides with the intention to poison stray dogs, but instead of that he poisoned at least 21 vultures. That meant the end of vultures in Bosnia and Herzegovina, because in the following years 40 dead vultures were found in that territory as a consequence of such poisoning.
In the Croatian Karst, vultures almost entirely depend on sheep as their food. Sheep encounter an increased mortality in conditions of extensive livestock breeding. But with intensive breeding (which means adding feed in winter, increased use of medication, fenced enclosures for animals giving birth, etc.) vultures have remained without food. Increased veterinary control (prevention) also adds to poisoning of vultures.
Vultures have a wing span of almost 3 meters, which is an advantage, because they are looking for food cruising and sailing on air currents like gliders, so that they spend only 1/30 of those energy, which they would need in an active flight (like sparrows or pigeons). But this wing span can be fatal if a vulture touches an electric wire with its wings (wet feathers) in rain or fog, when flying near wire transmission lines, the number of which constantly increases. It is possible that these lines break fragile, hollow bones in wings, which means a slow death from starvation, lying somewhere under the pylons. However, if the bird touches with its wings "phase and neutral" at the same time, the electricity causes their burning. The electric current has become a very frequent cause of death among vultures.
Each year a large number of vultures fall into the sea. Vultures do not know how to swim and if nobody comes to their rescue in the first hour, they drown. In the area of Kvarner we are able to rescue ten vultures on average, which afterwards spend a few months in the rehabilitation centre. Why do they fall? Usually due to some kind of disturbance. Sometimes tourist boats are racing close to the cliffs where vultures are nesting just 10 meters above the sea level. Or yachts are anchored in small sandy bays inside ornithological reserves. It even happens that boats crowded with tourists stand under nests, while excited tourists are shouting, using horns, etc. with the intention to cause vultures leave their nests, so that they would be able to take photos. Ships with divers are anchored for days under cliffs, while divers are diving. In this way they are disturbing parent vultures, who are not able to bring food to their offspring. Or these young vultures get scared and leave the nest too soon and consequently fall into the sea.
During five years of wandering, a large number of young vultures suffers from hunger and exhaustion. One vulture, marked in Kvarner, was killed by a vehicle on the highway near Nice, on the Cote d'Azur. It landed on the road, probably totally exhausted and wanted to eat a small animal, which had been run over by a car.
In efforts for protection of nature, it is very difficult to prevent invasion of civilisation into once pristine nature. People immediately oppose such attempts saying, that environmentalist prevent development and progress, "which is necessary". They generally oppose any environmental activities against mobile phone lines, against nuclear energy or against building hydroelectric power plants and thermoelectric power plants, highways, ...). First of all, progress is not necessary; it is that people simply want it, regardless of the consequences. The natural habitat of vultures is being destroyed due to construction of new roads, opening of new quarries, construction of new power lines and wind turbines.
Wind turbines have become the main cause of death in areas where vultures usually glide and search for food.
However, the protection of griffon vultures in the Kvarner region, carried out by the association Gyps fulvus – Research-educational centre for the protection of griffons and nature in cooperation with the Institute for Ornithology at the Croatian Academy of Sciences and Arts (HAZU), after nearly 30 years of efforts finally shows some results. The number of breeding pairs has increased in Kvarner from 70 to 130. This gives one hope and optimism.