The mature male goldeneye has an iridescent green head with a prominent white patch between bill and eye. Its back is black and the neck and underparts white or pale grey. The female has a mainly grey body with a chestnut brown head. As the name suggest, the eyes are golden yellow and the short bill and sloping forehead give the head a triangular look. The flight of the goldeneye is rapid and direct with a noticeable wing rattle. The light underparts show up in flight.

I am grateful to Eric Begbie who allowed us to use this information which is reprinted from 'Fowler in the Wild'.