The increase in the Spanish population of Griffon Vulture Gyps fulvus during 1989–1999: effects of food and nest site availability

Abstract

Between 1989 and 1999, the Spanish population of Griffon Vulture Gyps fulvus increased from 8,064 to 22,455 breeding pairs. This increase was not linked to any clear density-dependent process of population control given that the population grew more steadily in the more densely occupied sectors. This growth was related to a small increase in the breeding range of the species supporting the strong effect of the availability of nesting sites in limiting the range of the species. Around 85% of the breeding pairs were restricted to limestone sectors where cliffs suitable for breeding colonies were more abundant. In these limestone sectors, changes in the number of breeding pairs were positively correlated to changes in livestock abundance during 1989–1999, supporting a functional relationship between food availability and vulture abundance. Any active destruction of livestock carcasses to prevent the spread of some epidemic livestock diseases (e.g. bovine spongiform encephalopathy, African swine fever, foot and mouth disease) will probably produce a concomitant reduction of the Spanish population of Griffon Vulture.