The bearded vulture (Gypaetus barbatus) also goes by the colorful name of ossifrage or bone-breaker, in honor of its singular diet. As the only scavenger to feed exclusively on the marrow of carrion bones, it has developed a particularly close relationship with large flocks of sheep or goats. Although itself no threat to human activities, it has been a collateral victim of practices like the laying of poisoned bait against wolves, as well as the deterioration of its habitat. In the course of the 20th century it disappeared from most of Europe’s mountain regions, surviving almost solely the Pyrenees. It was this situation that inspired a group of “firmly motivated and committed” naturalists to join forces in 1995 “to prevent the bearded vulture’s extinction in Spain” in the words of Gerardo Báguena, current president of the Fundación para la Conservación del Quebrantahuesos (FCQ).
Since then, the FCQ team have developed original techniques unknown to all but a few specialists worldwide. In perilous climbing expeditions in the Pyrenees, weighed down with special incubators, they rescued some fifty eggs with scant chance of surviving in the nest; raised the chicks on a diet of bones from the time they weighed just a few grams, and instructed them in the habits of their species. Finally, they reintroduced them to into the wild, thereby staving off the threat of extinction.
“Spain’s bearded vulture population has grown by over 200% in these 25 years,” Báguena points out, with numbers jumping from 50 pairs in 1995 to 140 in 2019. Working with scientists from affiliate centers of the Spanish National Research Council (CSIC), FCQ experts have added to our understanding of the biology of a species occupying a unique ecological niche, through recourse to such ingenious techniques as placing egg-shaped sensors in the birds’ nests after removing the real eggs to be reared in captivity. The mother bird incubates these spy eggs, which record and transmit large quantities of data – e.g., temperature and number of times the egg rolls over – so the human breeders can replicate in real time what happens in the nest.
Another practice to prove successful was the separation of eggs in the event of a double clutch. The female vulture generally lays a single egg, a difficult process during which she “shrieks and twists,” says Báguena, echoing the observations of FCQ naturalists watching through telescopes. But at times she lays two eggs and both chicks are born healthy. This gives rise to what Báguena describes as a “harrowing” selection process in which one chick kills its sibling without the parent birds intervening.
“It may be distressing to watch,” Báguena remarks, “but we cannot interfere with nature.” By contrast, when FCQ experts rescue eggs from a double clutch the chicks are born and fledged separately. The results are encouraging. When freed on reaching adulthood, the birds show no aggressiveness: “We see the two siblings flying together in the knowledge that, left on their own, one would certainly have died in the nest.”
FCQ’s efforts were crowned with the first wild birth of a bearded vulture in the Picos de Europa National Park, where the original population had gone extinct over fifty years before. The chick was a female, born on 14 March last, and named the welcome one, ‘Bienvenida’ in Spanish. “We wanted to celebrate a new era,” Báguena explains. “Behind us lies a time of extinctions; the bear, the Pyrenean ibex … now all that is changing, and we hope the recovery will gather pace.”
The 15 specialists of Fundación Conservación del Quebrantahuesos can name “each and every one” of the 26 specimens making up the new Picos de Europa population, and can even recognize them in flight. “We watch them with telescopes and precision optical equipment. They are simply magnificent.”