A thrush-like, ground-dwelling warbler, Seiurus noveboracensis (family Parulidae), which breeds in woodland bogs and swamps in Canada and the northern U.S.
Origin
Mid 19th century; earliest use found in Galaxy Magazine.
Definition of northern waterthrush in US English:
northern waterthrush
noun
A thrush-like, ground-dwelling warbler, Seiurus noveboracensis (family Parulidae), which breeds in woodland bogs and swamps in Canada and the northern U.S.
Origin
Mid 19th century; earliest use found in Galaxy Magazine.