The California gull (Larus californicus) is a medium-sized gull, smaller on average than the herring gull but larger on average than the ring-billed gull, though it may overlap in size greatly with both. It breeds breeding around lakes and marshes in interior western North America from the Northwest Territories, Canada south to eastern California and Colorado. It nests in colonies, sometimes with other birds. Adults are similar in appearance to the herring gull, but have a smaller yellow bill with a black ring, yellow legs, brown eyes and a more rounded head. It is migratory, most moving to the Pacific coast in winter. It is only then that this bird is regularly found in western California.