Northern Canada, from Banks I east to northern Hudson Bay and northern Baffin I (east to vicinity of Home Bay), north through Ellesmere I to western Greenland (near Thule). Winters on Pacific coast, from British Columbia to Baja California.
Thayer's Gull (Larus thayeri) [XC403359]
by id from Garry Point Park, Richmond, Greater Vancouver, British Columbia, Canada (begging call)
Nest
A cup of grass or other available vegetation placed on a rocky cliff ledge usually on the coast, or surrounding a near-coastal freshwater site, Often nests on cliff below colonies of Glaucous Gull (Larus hyperboreus).
Subspecies
Larus glaucoides (Sibley and Monroe 1990, 1993) has been split into Iceland Gull (Larus glaucoides) and Thayer's Gull (Larus thayeri) following AOU (1998).
A highly controversial and variable taxon, alternatively treated as a subspecies of Herring Gull (Larus argentatus) or of Iceland Gull (Larus glaucoides). Interbreeds with subspecies kumlieni of Iceland Gull (Larus glaucoides) in northern Hudson Bay and eastern Baffin I, prompting some to treat it as a subspecies of Iceland Gull (Larus glaucoides).
Considered by some authors to be a subspecies of Iceland Gull (Larus glaucoides).
BirdLife International Species Factsheet