
Gadwalls may appear similar to hen mallards, but can be distinguished by their colourful speculum feathers.
Gadwall
Gadwall 
Anas strepera
The gadwall, or "grey duck", is a greyish-brown, mid-sized dabbler with a wide distribution across western North America. It is most readily identified in flight by the white feathers of the speculum adjacent to the body. Forward of the speculum is a chestnut-coloured patch. Yellow legs and feet are also distinctive features. The gadwall is noted for its colonial-like nesting on islands in some Prairie wetlands.
