On the 29th of September staff from the French Pyrenean municipally of Arreau saw a bearded vulture landing on a school roof and then falling on the ground. The bird was immediately collected by Mr. Roland and Jean Claude Alberny, owners of the falconry «Les Aigles d’Aure». The day after the bird was picked up by staff from the wildlife recovery center Hegalaldia.
The bird, an adult female named Yaga, had been captured and tagged by the Fundación para la Conservación del Quebrantahuesos (FCQ) in September 2015 in Aragón (Spain), with large patagial (wing) marks, one alu-ring on the left leg and one long plastic ring on the right leg, and with a back harness with a GPS tag.
The bird had a severe injury on the sternum, with necrosis and deformation caused by the harness. Further the leg where the long plastic ring was installed was swollen. The harness as well as the plastic ring were immediately removed and an adequate therapy was initiated. Analysis of its blood also revealed severe lead intoxication - 1703 μg/L, although no lead pellets could be observed through the x-ray done. Immediately a treatment with Ca-EDTA was started. In the end, Yaga was found because of lead poisoning, although it had severe lesions that would probably also end up killing it.
This episode is significant for two reasons
1) It again shows that lead poisoning (from hunting ammunition) is a significant threat to bearded vultures. Our own data from the Alps suggests the same, including the potential for some population-level impacts.
2) It alerts that badly-put tag harnesses or rings can cause severe injuries in birds – relevant for all the conservationists that study and monitor these birds
The VCF also uses tags and rings – although we decided not to use wing tags due to its potential impact on the birds. All the birds released in our reintroduction projects (Alps, Corsica, Grands Causses, Andalusia) are tagged with GPS to allow us to monitor their movements and detect any persisting or new threats which could jeopardize their survival. The obtained data has been helping us to identify specific threats and define the best methods on how to fight against them.
Nevertheless, the welfare of the individual has to be always above the scientific interest as well data collection. By installing a GPS or wing tag we should always consider potential impacts on its flight capacity.
It is well known that adult female bearded vulture enlarge their chest when they reach sexual maturity. This makes it very difficult to calculate in advance the length of the harness (if fixed on the back) if the bird is tagged when young. Further, weight changes can occur in a short time - one recovered adult female at the recovery centre of Vallcalent, managed by the VCF, increased from under 5kg at arrival to 7kg 1.5 months later (40% increase!).
The VCF then adopted the leg harness method, after testing it on several birds in captivity, after observing no negative impacts. We suggest that in the species the GPS should be fixed with a pelvis harness, region where volume change during the lifespan of the bird almost doesn’t occur as soon the bird has completed its growth. In all our reintroduction projects (Alps, Corsica, Grands Causses and Andalusia) birds are tagged with this method.
The VCF is now discussing with the FCQ tagging methods – while we will continue to lobby for a ban on hunting with lead ammunition.
As for Yaga, the story ended up well - on the 27th of November, following two months of recovery at the Hegalaldia center, the female could be successfully released at the French Pyrenees, near the ski station Pla d'Adet (Saint-Lary Soulan). Yaga was released without any GPS tag this time.
The release of Yaga was attended by dozens of people, and all enjoyed seeing her fly off to where she belongs: the Pyrenees