Abbott's Booby Papasula abbotti is a relictual species now endemic to Christmas Island, Indian Ocean, and one of the world's most threatened seabird species. While actual and potential threats to the species on Christmas Island are being managed, no conservation measures concerning the marine habitat of the birds, such as the delineation of marine Important Bird Areas (IBA), are currently being implemented as knowledge on the foraging areas of Abbott's Booby has been scarce. Using GPS-loggers to track Abbott's Boobies during their foraging trips, the present study provides detailed information about the foraging movements of the species during early chick-rearing. The birds foraged relatively close to the island with a median range of 56.8 km (range = 3.6-56.7 km). They chose trip directions according to their nesting sites in the north and south of the island and foraged preferably in north-westerly and south-easterly directions of Christmas Island, respectively. Applying the protocol of BirdLife International, the tracking data were used to identify a potential IBA for Abbott's Booby during early chick-rearing. According to the small foraging distances and the limited range of trip bearings, the delimited IBA was relatively small, encompassing only a narrow corridor of about 4,500 km(2) to the north-west and south-east of Christmas Island. Given the small size and low economic relevance of this area, the delineation of this IBA appears feasible and would be an important first step to protect Abbott's Boobies at sea as well as the species' foraging habitat.
