Its bill is narrow and black. Teals are sexually dimorphic. Males have a cinnamon colored head with an iridescent green crescent spanning from one eye, around the back of the head, to the other eye. The sides and back are actually marked with tiny black and white stripes, although they appear grey. Their wings and tail are a tannish-brown color, with pale yellow feathers along the side of the tail.
Females are entirely tannish-brown, except for their white chin and belly.
Green-winged Teals feed on almost any plant or animal in high abundance, largely in shallow waters, near the shoreline or in mudflats. Their main foods vary from region to region, depending on what is available, but they consist mainly of marine invertebrates and seeds of marine vegetation. The finely spaced lamallae along the inside of the Teal's bill allow it to retrieve small seeds easily. Green-winged Teals begin courtship between September and November. They form monogamous pairs every winter.