The Pacific wren (Troglodytes pacificus) is a very small North American bird and a member of the mainly New World wren family Troglodytidae. It was once lumped with Troglodytes hiemalis of eastern North America and Troglodytes troglodytes of Eurasia as the winter wren.
It breeds along the Pacific coast from Alaska to California and inland as far as Wyoming and the Black Hills of South Dakota. It migrates through and winters across the western half of the United States and Canada.
The scientific name is taken from the Greek word "troglodytes" (from "trogle" a hole, and "dyein" to creep), meaning "cave-dweller", and refers to its habit of disappearing into cavities or crevices whilst hunting arthropods or to roost.