By Mark Baschuk and Stuart Slattery, Ph.D.
are vital to waterfowl in many ways beyond their essential role in flight. They provide insulation, flotation, and camouflage, and drakes use their brightly colored breeding plumage to attract mates. While feathers are remarkably durable, they eventually wear out over time.
Waterfowl replace their old plumage with new feathers at least once a year during a process known as molting. Whistling-ducks, geese, and swans undergo a single annual molt, replacing all body, wing, and tail feathers shortly after the nesting season. Most ducks, however, undergo two molts a year. The first molt occurs shortly after nesting. Drakes trade their gaudy breeding plumage for drab brown feathers known as "basic" or "eclipse" plumage. The second molt occurs from fall to early winter. Only the birds' body feathers are replaced during this molt, in which drakes develop their brightly colored "alternate" or "nuptial" plumage. Of course, there are exceptions to these molting patterns in ducks. For example, drake ruddy ducks develop their alternate plumage in spring, while drake long-tailed ducks molt their body feathers three times a year.