Taxonomy
Blue duck © Martin, Creative Commons Attribution-NonCommercial License - Version 2.0
The blue duck is unlike any other duck. It is the only member of its genus and has no close relatives. It is an almost uniform slate blue-grey duck with a characteristic pale bill.
Morphology
Male and female blue ducks have a similar appearance with the following characteristics:
- almost the entire plumage is slate blue-grey
- the head is a little darker and crown and nape washed with brown
- the breast is mottled with chestnut (reddish-brown) spots that are denser and more extensive in the male
- the undertail coverts are also chestnut
- the secondaries are tipped with white, and inner secondaries and tertials have a thin, black outer margin
- the bill is pinkish-white with black tip and flaps of skin at the side towards the tip which assist its feeding technique
- legs and feet are dark grey with black at joints
- eyes yellow
