In 1986, captive-bred bearded vultures began returning to the Alps after the species had disappeared from the mountain range decades earlier. The reintroduction programme released young birds at sites across the region, with the first successful wild breeding recorded in 1997. By 2021, researchers estimated that 344 bearded vultures were living in the Alps, including 65 breeding females. Wild-hatched birds increasingly drove the recovery, helping establish a population researchers describe as demographically self-sustaining. Yet the recovery has not been uniform, and scientists warn that differences in survival and continuing threats could still shape its future.
Alps bearded vulture population reaches 344
According to the study published in the British Ecological Society, titled ‘Demographic assessment of reintroduced bearded vultures in the Alps: Success in the core, challenges in the periphery’, the scale of the recovery became clearer when researchers reassessed the population using data collected over many years. Their analysis estimated that 172 female bearded vultures were alive in the Alps in 2021, including 65 breeders. Assuming an equal sex ratio, this produced an estimated total population of 344 birds, with a 95% credible interval of 294 to 396. The study also calculated a mean annual population growth rate of 0.083 between 2002 and 2021.The increase was increasingly being driven by birds born in the wild rather than by the released birds themselves. The researchers found that wild-hatched individuals increased faster than released individuals. In the core Alpine area, wild-hatched birds had already exceeded released birds by 2009, although the situation was different in the periphery, where released birds still outnumbered wild-hatched birds in 2021. This shift towards naturally produced birds was central to the researchers’ conclusion that the re-established population was “self-sustaining from a demographic point of view”.
Population growth was slower in the Alpine periphery
The 344-bird estimate did not mean that recovery had happened evenly across the entire Alpine range. The researchers divided the study area into a core, covering the central and north-western Alps, and a periphery covering the southern and eastern Alps. The population grew more rapidly in the core, where the mean growth rate was estimated at 0.093, compared with 0.051 in the periphery. Adult survival was also substantially higher in the core.The researchers linked some of these differences to environmental conditions. Areas with large ibex populations can provide an important food supply because the birds feed on bones and carcasses, while limestone landscapes offer suitable surfaces on which vultures can break bones to obtain marrow. Human pressures may also have played a role: the study notes deaths associated with poaching, illegal poisoning, lead poisoning and collisions with cables and power lines, with such pressures appearing greater in the peripheral areas.
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Alpine bearded vulture population becomes self-sustaining
The Alpine reintroduction had established a demographically self-sustaining population. However, the researchers stressed that this did not mean every part of the Alps had reached the same level of independence. The peripheral population remained dependent on additional releases at the time of the assessment, while releases in the core were predicted to have little demographic effect. The researchers also noted that continued releases could still have genetic benefits because genetic diversity in the population remained low.The recovery also remains vulnerable to additional mortality. The researchers found that adult survival is driving population growth. Their modelling showed that relatively small increases in mortality could change the population’s trajectory, while threats such as wind-turbine collisions and illegal poisoning could create additional risks. As the researchers put it, the reintroduction had succeeded in creating a self-sustaining population; monitoring and efforts to prevent avoidable deaths remain important to keeping that recovery on track.
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