Migratory and Winter Movements of Arctic Alaska Breeding Sabine's Gulls (Xema sabini)

The Sabine's Gull (Xema sabini) is a pelagic, Arctic-breeding species with a circumpolar breeding distribution. Little is known about migration routes for northern Alaska-breeding Sabine's Gulls. We tagged Sabine's Gulls on their northern Alaska breeding grounds to identify migration routes and wintering areas and compare geolocators and GPS pinpoint tags for use on small-bodied gulls. Twelve geolocators were deployed in northern Alaska in 2011 (Colville River delta) of which four were recovered, and five GPS pinpoint tags in 2021 (Qupaluk). Although the GPS pinpoint tags provided more accurate locations allowing for finer-scale habitat evaluation, and did not require recapture of birds, the overall coverage provided by geolocators was superior given constraints on the number of locations GPS pinpoint tags record. Broadly, Sabine's Gulls migrated away from the breeding grounds as expected, passing along the west coast of Alaska and south along the west coast of the Americas to winter in the Humboldt Current off the coast of Peru. Our tracked gulls used the same migratory staging and wintering areas as did Sabine's Gulls breeding in the Canadian Arctic (Davis et al. 2016). Such reliance on specific marine areas presents risks from climate-related changes or ecological damage to those areas.