干旱区生态环境知识资源中心

Nearly fledged Gory’s Shearwater Calonectris diomedea chicks at Selvagem Grande occasionally desert their nest sites during the night, but generally return before dawn. The temporary use of other nest sites is rare and lasts less than two days. Almost all chicks from Selvagem Grande return to the island for their first breeding attempt; very few breed at islands outside the archipelago. On Selvagem Grande, almost half the males return to their native colony whereas more than 90% of females recruit to other colonies. Inter-colony movements sometimes exceed 1 km, but, if they return to their native colony, both sexes settle within 20 m of their natal site. From the second breeding attempt onwards, most birds of both sexes are faithful to the nest site. On average, less than 20% of birds desert their former nest site each year, with a shift of about 4 m only. Most nest shifts follow a breeding failure or a temporary respite from breeding, and are accompanied by a switch in partners.