The Green-winged TealAnas carolinensis is a common and widespread duck that breeds in the northern areas in North America. This dabbling duck is strongly migratory and winters far south of its breeding range. It is highly gregarious outside of the breeding season and will form large flocks. In flight, the fast, twisting flocks resemble waders. This is the smallest North American dabbling duck. The breeding male has grey flanks and back, with a yellow rear end and a white-edged green speculum or colored wing patch, which is obvious in flight or at rest. It has a chestnut head with a green eye patch. It is distinguished from drake Common Teals by a vertical white stripe on side of breast, the lack of both a horizontal white scapular stripe and the lack of thin buff lines on its head. The females are light brown, with plumage much like a female Mallard. They can be distinguished from most ducks by size and shape, and the speculum. Separation from female Common Teal is problematic. These photos were taken at the San Joaquin Wildlife Sanctuary in Irvine, CA.