Breeds n. Canada. Scarce in winter to s. ID: 4-year gull. Size and shape as largest ICGU's. Id from the latter with great caution and as follows: adult often has hooded appearance (nonbr), most (80%) have dark iris, extensive black wing-tips (with white 'tongues'), slightly darker back. Juv: darker brown, dark-centered tertials and primaries contrast with rest of bird, solid tail band. From HEGU by size and shape, bill size/color, dark iris, wing-tip pattern (whitish underwing usually most striking).