N. species, fairly common in Canada, scarce winter visitor s. of border. Big and hardy. Occasionally hybridizes with HEGU (‘Nelsons Gull’). Compare with ICGU. Leucistic and worn birds can be a problem. ID: 4-yr gull. Large size (usually bigger than HEGU) and pale wing-tips usually diagnostic. Compared to ICGU has much longer bill and flatter head giving fierce impression. Longer-tailed with a more tapered rear end (less pot-bellied). Shorter wing point and primary projection. Ad: white flight feathers contrast strongly with pale gray upperparts. Striking in flight. Head usually lightly streaked in winter. Pale yellow bill with weak red spot. 3rd-yr: as adult with some imm feathers and dark on bill. Juv: (commonest plumage seen in US) finely patterned internal feather markings on creamy buff, which fade to white through winter. Always striking 2-tone pink bill with well-defined black tip. Eye often appears small on large head. Dark iris. By late winter darker markings fade and can appear strikingly white. 2nd-yr: similar but has uniform gray mantle and pale iris.