Iceland Gull adult
On berm below dam with Herring and Ring-billed gulls (Iceland is the Herring-type on the right). Initially discovered in this position by white underside to folded primaries; note black and white underside to primaries of Herring (four birds left) and Ring-billeds.
Also note the mildly brighter and deeper reddish tones to the feet and legs compared to the Herring. The Iceland was a bit smaller and more petite in build than the Herrings.
Occasionally the bird would stretch a wing to show the characteristic underwing pattern (see following images).