POPULATION VIABILITY ANALYSIS OF CAPTIVE AND RELEASED BEARDED VULTUREPOPULATIONS

With the computer program VORTEX I ran a series of simulations of the bearded Vulture (Gypaetus Barbatus) population held in captivity in Eu ropean zoos and of the population released in the Alps. The simulation s showed that the risk of extinction of the captive population with th e extraction rates currently in use is low. It seems possible to maint ain the current release rate of two fledglings per year at each of the four release sites in the Alps, but it does not seem possible to incr ease the release rate by expanding the project to other European mount ains without dangerously depleting the captive population. The models showed that the most effective way to increase the release rate withou t increasing the captive population size is by improving hatching succ ess in captivity. The information on the demographic parameters of the Bearded Vulture population released in the Alps was not good enough t o predict the ultimate fate of the present population or to allow for recommendations on how long the population should continue to be suppl emented. Although it will be necessary to wait some years to see if Be arded Vultures are able to breed in the wild in the Alps and to estima te fecundity rates, it should be possible to improve the monitoring of the individuals released to obtain more-precise survival estimates. T he models of the captive and released population also showed that it s hould at least be possible to have an artificially supplemented Bearde d Vulture population in the Alps, but because this is not the goal of the present reintroduction project, the organizations involved should decide whether this a politically or economically desirable goal.