Kumlien's gull

Kumlien's gull (Larus glaucoides kumlieni) is a large gull which breeds in the Arctic regions of Canada. It is migratory, wintering from Labrador south to New England and west across the Great Lakes. The species is named after the Swedish-American naturalist Thure Kumlien. It is a regular vagrant in small numbers to Britain and Ireland.

It has variably been considered a full species, a subspecies of Thayer's gull, a subspecies of Iceland gull, and a hybrid between the aforementioned species. It is currently considered a subspecies of Iceland gull by the American Ornithologists' Union.

This taxon breeds colonially or singly on coasts and cliffs, making a nest lined with grass, moss or seaweed on the ground or cliff. Normally, 2-3 light brown eggs are laid.

The taxon is pale in all plumages, with a remarkably variable amount of pigment in the primaries. Individuals range from completely white-winged (indistinguishable from nominate glaucoides Iceland gull) to so dark in the wings as to be indistinguishable from Thayer's gull. Eye color is also variable, from pale yellow to dark brown. Such remarkable variation seems to lend credence to the belief that Kumlien's gull is in fact a hybrid swarm.