Aythya collaris, commonly known as the Ring-necked Duck, is native to North America. Its geographical distribution primarily includes regions in Canada and the United States, with breeding populations found in the northern areas such as the boreal regions of Canada. During the non-breeding season, the species migrates to more southern locations, reaching as far as Central America and the Caribbean.

The Ring-necked Duck typically inhabits freshwater environments. It favors shallow lakes, ponds, marshes, and wetlands that have abundant aquatic vegetation. During the breeding season, the preference is for boreal forest wetlands with emergent vegetation. In winter, they frequent larger bodies of water, including coastal bays and riverine environments.

As a diving duck, Aythya collaris primarily forages underwater. It feeds on a diet comprising aquatic plants, invertebrates, and seeds, adapting its diet according to seasonal availability. The species plays a role in controlling aquatic vegetation and invertebrate populations, contributing to the ecological balance of its freshwater habitats.