Feathers are a marvel of natural engineering, but they require constant care and must be replaced periodically to maintain peak performance. Waterfowl spend a couple hours each day just caring for their feathers. An oil gland at the base of the tail secretes a preening fluid that keeps feathers soft and pliable, which in turn prevents them from breaking, keeps them waterproof, and enhances their aerodynamics. Waterfowl use their bills to distribute this fluid throughout their feathers while preening. Ducks and geese also use their bills to realign their feathers and reconnect any Velcro-like barbules that have become separated.
But even with regular preening and other care, feathers break and wear out. Any feather that is pulled out or lost completely is replaced right away; broken and worn feathers aren't replaced until the birds molt. Molting, the natural process in which birds routinely replace some or all of their feathers, varies in timing and frequency among waterfowl species. All ducks and geese undergo a simultaneous wing molt, when flight feathers are replaced. During this period waterfowl are completely flightless—usually for a month or so—until new flight feathers grow in.
Ducks replace their contour feathers at least twice a year. During winter and spring many male ducks have gaudy breeding plumage, which serves to attract prospective mates. Shortly after the breeding season, however, males undergo a body molt, replacing their showy "alternate" plumage with drab "basic" or "eclipse" plumage. These henlike feathers help conceal drakes while they are flightless during the wing molt. But as soon as drakes can fly again in late summer, they begin a second molt and gradually develop their breeding plumage as fall progresses.
Female ducks molt as well, but differences between their basic and alternate plumage are far more subtle. Hens molt into their basic plumage just before nesting and keep this plumage until after the wing molt and brood-rearing activities are complete. Geese typically undergo just one complete molt a year, which has a much less noticeable effect on the birds' appearance.
Everyone who enjoys viewing ducks appreciates their colorful and in many cases iridescent plumage. Hunters have the privilege of examining these remarkable feathers in hand. The next time you bag a duck or goose, take a few minutes to explore the bird's many different kinds of feathers—and their colors and patterns. You'll once again be reminded of the wonders of nature.
A Kaleidoscope of Color
The plumage of ducks, especially that of drakes of certain species, displays stunning color and iridescence. A drake mallard's green head and its bright blue wing markings are prime examples. Why are some waterfowl feathers iridescent while others are not? The colors we see in the plumage of waterfowl are produced in two ways: chemically and structurally.
Chemical coloration is produced by pigments that either absorb or reflect wavelengths of light. White feathers, for example, have little or no pigment, so all wavelengths are reflected. In contrast, black feathers contain the dark pigment melanin, which absorbs light.
Iridescence is a structural phenomenon associated with the barbules on feather vanes. Iridescent feathers have numerous, overlapping barbules that reflect and absorb light in varying amounts. The result is a lustrous shine that changes color depending on the intensity of the sun and the angle at which the feathers are observed.
David Brakhage is director of conservation programs at DU's Great Lakes/Atlantic Regional Office in Ann Arbor, Michigan. Conservation intern Elizabeth St. James provided research assistance for this article.
View more waterfowl feather photos in our Feather Details slideshow.