Mareca Stephens, Gen. Zool. (Shaw), xii, pt. 2, p. 130 (1824).
Type by orig. desig., Anas penelope Linn.
In Mareca the bill is small, shorter than the head, depressed, and slightly tapering towards the tip ; the nail is proportionately large; the tail is short, cuneate and has fourteen feathers; the tarsus is rather short, scutellate in front; the hind toe is small with a narrow lobe.
Of the three species in this genus, two are confined to America,, whilst the third is found over the greater part of Europe, Africa and Asia.