Range Description: Cassin's Auklet - Ptychoramphus aleuticus

Summary of the extent of the breeding, wintering, migration and year-round range of this species in the Western Hemisphere, including Canada, U.S.A. and Mexico:

Canada - Resident year-round: 237,636 square km
Mexico - Resident year-round: 138,537 square km
U.S.A. - Resident year-round: 931,319 square km; Migration only: 546,116 square km