Barrow Island as an important bird area for migratory waders in the East Asian-Australasian flyway

ACKNOWLEDGEMENTS: We thank Chevron Australia (including the Gorgon Joint
Venture Partners) for funding this long-term project, and for logistical support including onsite accommodation and transportation. Particular thanks to Michael Craig for field work support, and to Harry Butler and Allan Burbidge and an anonymous reviewer for their comments that helped improve the manuscript. The views and conclusions expressed in this paper are those of the authors and do not necessarily represent the official policies, either expressed or
implied, of the listed organisation.
ABSTRACT: Little is known of the importance of continental islands to migratory birds off western Australia because few longterm studies on transequatorial migrants have been conducted in this region. In this study we report on the temporal and spatial use of a large offshore island off north-western Australia, Barrow Island, by migratory waders. While Barrow Island is a designated International Bird Area (IBA), little is known about the long-term seasonal abundance and distribution of waders using the island. The results of a three-year study lead us to propose that continental islands such as Barrow Island are important not just as staging sites but also as destination sites for four international migratory species. Twenty-two species of Holarctic-breeding waders and four species of migratory larids, among other non-migratory species, were recorded. Counts were highest during the southward migration and non-breeding periods in contrast to other island sites in northern Australia. Counts during the breeding period, when migrants move to northern latitudes, remained higher than has been recorded before, suggesting the island offers important “winter” habitat for non-breeding migratory waders. Our study suggests that the use of continental islands off north-western Australia by international migrants has been underestimated because the intra-annual and inter-annual records of island usage had not been recorded. The importance of Barrow Island within the East Asian-Australasian Flyway as an IBA can now be justified, based on the IBA criterion for congregations of Red-necked Stint Calidris ruficollis, and more than 1% of a biogeographic population of Red-necked Stint, Grey-tailed Tattler Tringa brevipes, Ruddy Turnstone Arenaria interpres, and Greater Sand Plover Charadrius leschenaultii. Our work also highlights the importance of seasonal observations of international migrants in the region, the role that continental island may play in this context, and potentially their importance in the East Asian-Australasian Flyway off north-western Australia.