The range of the Cinnamon Teal extends from Canada south to Tierra del Fuego. They nest both in South and North America. They have elongate bill and differing eye color between the sexes. The five races vary mostly in size, color intensity, and extent of black on the underparts. The familiar Northern Cinnamon Teal ( A.c. septentrionalium) occurs primarily west of the Rocky Mountains, where it essentially replaces the Blue-winged Teal. Large number winter in Mexico and Central America, but many of the southern breeders are basically resident. Largest and longest billed of the complex, Andean Cinnamon Teal (A.c. orinomus) is in the arid country of Peru, Bolivia and northern Chile, and are numerous in the lake Titicaca region. Smaller and deeper red drake Argentine Cinnamon Teal (A.c. cyanoptera) have a browner belly and the sides of the breast often show some dark spotting. Ranging from southern Peru and Brazil south to Tierra del Fuego, the ducks are quite common in Argentina, and thousands gravitate to some Peruvian lagoons.
Drake Tropical Cinnamon Teal (A.c.tropica) are noted for blackish underparts and their neck, breast and flanks can be heavily spotted. Smallest of the complex, they are restricted to the lakes and marshes of northwestern Colombia. The western Colombian Borrero’s Cinnamon Teal (A.c. borreroi) are confined to the Andean highlands.
The quiet and trusting Cinnamon Teal gather in large flocks and are relatively slow to take alarm. They normally avoid regions with low temperatures and high humidity. The Teal are abundant in shallow marshes of the western inter-mountain plains. More than half of the ducks breed in Utah, where nest predation by California Gulls can be extensive. Pairs are partial to shallow lakes, ponds, sluggish creeks, reservoirs and irrigation ditches. They nest in isolation. Their nests are tunnel entrances, and are commonly located on islands with high grass cover.