New-What You Need to Know About Moulting in Waterfowl

                                   By Lou Horton

First things first: moulting refers to the process in birds of replacing plumage. All birds must moult periodically to replace plumage which is becoming worn and therefore may not be as protective as it needs to be.

Most species of birds moult once each year. Some species of waterfowl, however, moult twice each year. The first moult usually takes place in early summer and involves the replacement of all the plumage including the flight feathers. When the flight feathers are dropped all at once, the birds are rendered flightless for a period of weeks until they grow back. The inability to fly makes the birds more vulnerable to predators. Some species of ducks have developed a way to permit the males to take on a more somber color like their mates, affording them some protection. When male ducks take on muted colors during the summer, they are said to be in eclipse plumage. Later in the summer and early fall, they will undergo a partial moult which will return them to their more gaudy nuptial plumage which they need during the breeding season to attract mates. Not all species of ducks undergo a second moult but any type derived from the Mallard (all domestic ducks except the Muscovy can be traced back to the Mallard) do so. The two members of the genus Aix also do so. The Mandarin and Wood Duck also take on plumage which closely resembles that of the female. As a matter of fact, the red bill color of the normal male Mandarin is the most obvious tip-off that he is a male during the time he is in eclipse. In White Mandarins, it is more difficult to tell the sexes apart during eclipse since both sexes have pinkish red bills. It is my experience that the male often has a deeper shade of pink in his bill but I would hesitate to trust that as a primary way to sex them before the males take on their nuptial plumage. In both Mallard derivatives and Mandarins (Woodies too), the young male’s first adult plumage is eclipse plumage. Like the adult males, the young males will begin to take on their nuptial plumage as the cooler and shorter fall days begin. Even those Mallard derivatives in which both males and females are the same color ( including Black East Indies and White Calls, among others)  the males will undergo a subtle moult of body feathers in the fall. In young East Indies and Cayugas, the second moult is when they are clothed in their fine emerald sheen- the juvenile feathering is more more of a dull black. I also believe that females undergo a minor moult of body feathers along with the males.

How Moulting Affects Flock Management

When ducks and geese are moulting, they are under considerable stress. Their bodies are devoting a great deal of energy to the production of the new plumage. When you remember that the moult usually takes place at the conclusion of the breeding season when both sexes have fat reserves already depleted, you can understand why the moulting process is a very stressful time for waterfowl. In my experience, waterfowl also moult more intensively than do chickens and most other land fowl. They tend to drop their feathers more quickly and they re- grow all of their flight feathers at the same time which is not always the case in other species. That being the case, they need some tender loving care during the moult if they are to come out of it in the best shape. Do not put your waterfowl on a diet of whole corn during the moult. They need quality protein and some whole oats for the best results. I use a quality Duck Grower with an evening feeding of oats which they have access to overnight. If the birds (especially geese) have access to quality pasture they will benefit greatly. They also need plentiful supplies of fresh water to encourage bathing since you want them to oil and preen their new plumage as much as possible. Remember that Buffs need protection from the sun as they moult and afterwards or you will have some faded plumage in no time at all.