Location in Oregon
Blue is Winter range - Red is Summer range
Purple is Year-round range - Yellow is Migration range

Heermann's Gull

Larus heermanni - Common along the West Coast except in spring, when confined to Mexican breeding islands. Rare inland; often found offshore. The darkest gull, it is the only species that is uniformly dark below. The adult's white head is mottled in winter. In flight the black head and red bill of the adult is diagnostic, as are the narrow white terminal band and blackish underparts of the immature.