Eurasian wren
The Eurasian wren was formerly considered conspecific with two North American species: the winter wren ("Troglodytes hiemalis") and the Pacific wren ("Troglodytes pacificus"). Some ornithologists place the Eurasian wren, the winter wren and the Pacific wren in a separate genus "Nannus" that was introduced by the Swedish naturalist Gustaf Johan Billberg in 1828 with the Eurasian wren as the type species.