• The European water ousel. • A North American bird of the genus Seiurus, belonging to the Warbler family, especially the common species (S. Noveboracensis). • The pied wagtail. Found on http://thinkexist.com/dictionary/meaning/water_thrush/
Wa'ter thrush` (Zoology) (a) A North American bird of the genus Seiurus , belonging to the Warbler family, especially the common species ( S. Noveboracensis ). (b) The European water ousel. (b) The pied wagtail. Found on http://www.encyclo.co.uk/webster/W/14