Ship-assisted displacement of a Great Cormorant Phalacrocorax carbo and vagrant birds of subantarctic Macquarie Island

Abstract

Birds are known to use ships opportunistically as refuges during their migrations at sea, although detailed studies on these occurrences are limited. This study records the ship-assisted displacement of a Great Cormorant Phalacrocorax carbo from offshore south-east of Tasmania to the subantarctic Macquarie Island. Observations over a 3-day period aboard a resupply vessel showed the Cormorant used the ship as a resting platform, resulting in passive transport over 1260 km. To our knowledge, Macquarie Island is the southernmost location where this species has been recorded, and this sighting documents one of the possible pathways for vagrancy. We report detailed sightings of vagrant Great Cormorants on Macquarie Island and provide an updated list of vagrant non-marine waterbird and landbird species observed there since 2001. We discuss the role of human activities in influencing bird distribution and possible consequences of vagrant birds on remote ecosystems.