BILL MALFORMATION IN SCOPOLI'S SHEARWATER CALONECTRIS DIOMEDEA CHICKS

摘要

We report three cases of bill malformation in Scopoli's Shearwater Calonectris diomedea on Linosa Island (Sicily, Italy) that were found during monitoring of the colony over a 13-year period. The cases were observed in pre-fledging chicks; two of thebirds were also in poorer body condition compared with chicks of the same age. No adults in the colony have been found with similar bill malformations despite a much larger sample of recorded adults. We suggest that the observed malformations impair survival and that the chicks we encountered would likely starve after fledging. The frequency of bill malformation found on Linosa is less than one percent, which is consistent with cases reported in the literature for other species.