Northern Prairie Wildlife Research Center
The adult male hooded merganser in spring plummage is easily recognized by a large fan shaped white patch on its crested brown head.
In early fall the male resembles the female but gradually develops the characteristic white-and-black feather pattern, and by October some have the full breeding plumage. The hooded merganser is similar in size to the wood duck and average weights range from 1 1/4 to 1 1/2 pounds. It is considerably smaller than both the red-breasted and common mergansers which migrate through North Dakota each year. The hooded is the only merganser which nests in North Dakota.
The hooded merganser breeds along wooded lakes, streams and rivers over much of the United States and southern Canada. It winters in southern United States and Mexico and along the Atlantic and Pacific coasts. North Dakota counties in which hooded mergansers have been known to nest recently include McHenry, Barnes, Stutsman and Ward. However, they may nest or be induced to nest in other areas of the state where suitable habitats are found.
Like the other mergansers, the hooded is an excellent diver, and with its serrated and hooked bill is able to capture fish, its most important food. It also feeds on a variety of other foods, including crayfish, snails, frogs and aquatic insects.
Unlike wood ducks, hooded mergansers are not known to nest until two years old. Hooded mergansers, like wood ducks, nest in tree cavities. These cavities may be as high as 60 feet above the ground. The nest is made among the pieces of wood, bark or other debris found in the cavity and is lined with down the female plucks from her belly during egg laying and incubation. From 10 to 12 pure white eggs are laid, one each day. The hen begins full time incubation after the last egg is laid. At the start of the four-week incubation period, the male leaves the female.
Hooded merganser ducklings remain in the nest about 24 hours and then leave in a manner similar to wood ducks. The female remains with the ducklings for the next eight to ten weeks until they can fly. During this period, most of the time is spent on water. At first, ducklings eat mostly aquatic insects. As they mature and are better able to dive, fish, crayfish, and frogs become more important.