Up until rather recently this species was considered conspecific with the Olrog’s Gull (Larus atlanticus) of the Atlantic coast of South America and was then called the Band-tailed Gull. Belcher’s Gull is restricted to the Humboldt Current region, from southernmost Ecuador to northern Chile where it is common. It is coastal and often found in rocky situations, although it will forage to several km offshore. Of all gull species in this part of the world it is the most likely to forage in rocks at low tide, looking for various hard-shelled prey. As the old name implies adults of this species keep a black tail band throughout their life. The bill is long and straight, tubular-shaped, yellow with a large red tip. It is a blackish mantled gull, and the body appears white from a distance. In good light the body is actually seen to be pale grey, and the gleaming white head of the breeding season contrasts with the pale grey neck and belly color. In winter, even adults gain a well demarcated brownish hood, which highlights white eye crescents. It is a slimmer and smaller billed bird than the Olrog’s Gull.