Assessing the significance of the impact of Yellow-legged Gulls Larus m. michahellis on nesting Mediterranean Storm-petrels Hydrobates pelagicus melitensis on the island of Filfla

Abstract

Around 160 pairs of Yellow-legged Gull nest on Filfla, approximately one fourth of them (with an increasing tendency) in the boulder scree inside a Mediterranean Storm-petrel colony. Preliminary population estimates on the basis of capture-mark-recapture data and population models reveal a number of ca 17,000–20,000 Storm-petrel individuals for the Filfla colony. This number includes an unknown number of non-breeders and prospectors. At present, there are no data available whether the Filfla population is stable, declining or increasing. However, the concern lies with overall trends in seabird species from the tubenose family showing drastic declines around the world (Croxall et al., 2012).