Impacto dos predadores introduzidos na Ilha do Corvo no sucesso reprodutor das populações de cagarro (Calonectris diomedea borealis)

Mestrado em Gestão e Conservação dos Recursos Naturais - Instituto Superior de Agronomia / Universidade de ÉvoraIn the Corvo island, Azores, there are important species of seabirds classified as prioritary by the Annex I of the Bird Directive, for example Cory’s Shearwater Calonectris diomedea borealis, is one of the species that represents in terms of number and density the biggest expression in this archipelago in an European level. One of the major threats for the birds that reproduce in islands is the presence of predators, like rats, so, in this context, we analysed the variables that could explain the distribution of rodents, identified the accessible places of nesting of Cory’s, monitored the reproductive season and tried to understand the causes of fail in the egg and chick phase. The results point out a positive relation between rat abundance and reproductive success of Cory’s. The characteristics of the reproductive season are similar to those described for Berlengas and Selvagens, but they differ in the hatching success and chick success. We verified that in the first days of life of the chicks the predation is very significant and other variables should be taken into account, for example the predation by cats.A dissertação de mestrado que aqui se apresenta foi desenvolvida no âmbito do projecto LIFE+ NAT/P/00649 Ilhas santuário para as aves marinhas financiado ao abrigo do programa LIFE e coordenado pela Sociedade Portuguesa do Estudo das Ave