The Winter Wren (Troglodytes hiemalis) is almost identical to the Pacific Wren (Troglodytes pacificus) and Eurasian Wren (Troglodytes troglodytes), and the three were considered the same species until 2010.
Genetic and other evidence prompted researchers to split them into the Pacific Wren of western North America, the Winter Wren of eastern North America, and the Eurasian Wren of the Old World.
The Winter Wren is easily distinquished from the House Wren by its smaller size, shorter tail and the lack of a white eye-ring.

Pondicherry Wildlife Refuge, Jefferson, New Hampshire, USA, 4 August 2017