The Cinereous Vulture (Aegypius monachus) – also known as the Black Vulture and the Monk Vulture – is the largest bird of prey in Europe. Once abundant, its populations in Southern Europe have declined dramatically since the late 1800s. While globally, this vulture is classified as “Near Threatened,” in Bulgaria it has been considered extinct since 1985.
However, due to a re-introduction initiative started in 2015 by three Bulgarian non-governmental organizations – the Green Balkans, the Fund for Wild Flora and Fauna, and the Birds of Prey Protection Society – the vulture is finally back in the country, with 72 individuals imported from Spain and European zoos and released in strategically-chosen locations in the Eastern Balkan Mountains and the Vrachanski Balkan Nature Park in northwestern Bulgaria.
While 63 juvenile vultures were brought from Spain, where they had been found in distress and rehabilitated in aviaries, nine were captive-bred in zoos and afterwards released by means of “hacking,” a process involving artificial nests from which fledglings can gradually get back to the wild.
In a new study published in the Biodiversity Data Journal, scientists reported on and discussed the effectiveness and challenges of different release method, while offering new insights on the conservation and re-introduction of this iconic species. According to the experts, hacking proved ineffective for establishing an entirely new core population in the Balkan Mountains, and it did not work properly for supplementing a small settled group of individuals either. By contrast, the aviary method and delayed release – in which captive-bred birds are introduced to a new environment after a period of acclimatization – seems to be a much more efficient alternative.
“The Cinereous Vulture re-introduction establishment phase in Bulgaria in the two first release sites is running according to the plan, and the first results are satisfactory,” the authors wrote. “Two distinct nuclei are now created, and the species started breeding, which might be a reason to up-list it in the Red Data Book of Bulgaria from ’Extinct’ to ‘Critically Endangered.’”
These newly created nuclei in Bulgaria are the second and third of their kind in the entire Balkan Peninsula, after the breeding colony in the Dadia-Lefkimi-Soufli Forest National Park in northeastern Greece. Future exchanges between these three colonies will likely increase the regional population and ensure long-term stability of this species.
However, further monitoring and adaptive management are necessary for the long-term persistence of the new Black Vulture population. After the core breeding populations will start producing about ten chicks each year and the locally fledged individuals will begin reproducing on their own, it can be officially confirmed that this species has successfully re-established in the country.
By Andrei Ionescu, Earth.com Staff Writer
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