Incubation period unknown. Precocial young are tended by the female only, and may be deserted before attaining flight. Age at first flight is unknown. Minimum breeding age is thought to be 2 yr. Little information found.
Some adults die from internal parasites and floating oil.
Few are taken by hunters. Ducks, geese, and swans of North America. Stackpole Books, Harrisburg, PA. 544pp. Cogswell, H. L. 1977. Water birds of California.