Migration and Winter Habitat Use of Glaucous-Winged Gulls (Larus glaucescens) from Triangle Island, British Columbia

Abstract. Understanding the movements and habitat use of marine birds is essential to inform conservation and marine spatial planning. Here, satellite transmitters were used to study the migration and winter habitat use of adult Glaucous-winged Gulls (Larus glaucescens) from a colony in central British Columbia. Three of four tracked gulls overwintered locally, while the fourth followed a coastal migration route to northern California. All four gulls maintained small winter home ranges and spent an average of 72% of their time in nearshore coastal waters (average distance to coast: 0.6-1.7 km) characterized by low levels of anthropogenic activity. The remainder of their time was spent in naturally vegetated areas. One gull overwintered in an area with high human population density (northern California), with limited use of cropland (4% of locations) and urban (6% of locations) areas. This study is part of on-going efforts to understand the distribution and habitat use of marine birds throughout British Columbia to inform marine spatial planning and associated threats at various scales.