The Bufflehead (Bucephala albeola), often known to hunters as the “butterball” for its ability to put on quantities of fat during fall migration, is a small, stubby, strikingly-plumaged duck common in our area in winter—as long as there is open water. The odd name is a corruption of “Buffalo-head”, a reference to the bird’s angular, disproportionately large head.
The male (called a drake) and female (a hen) are of similar size and shape, but have such different adult plumages that one could be forgiven for thinking that they are two different species.
The drake is mostly a bright gleaming white, and boldly patterned with black on the back, wings, and tail. The forehead and lower border of the head has an area of darker coloration that, though it normally looks black, in the right light reveals beautiful iridescent highlights of bronzy-gold, purple, and green.
In contrast, hens and young drakes are a gray-brown on the underparts and a darker gray-brown on the rest of the body, save for a small white patch in the secondaries and a small oval of white on the side of the face.
During courtship, the drakes do a variety of rather charming displays, involving head-bobbing, wing-lifting, and short flights over and near the hen, with a short “water-skiing” finish, as the drake sticks his bright pink feet out in front of himself as he gradually comes to a stop on the surface of the water.
This bird breeds at the edges of ponds and lakes in the boreal forests of Canada. A cavity-nester like the Wood Duck, the Bufflehead’s small size enables it to use a wide variety of tree cavities for nesting—often abandoned flicker nest or roost holes. They migrate south in autumn to warmer climes. On its wintering grounds, the Bufflehead frequents lakes, ponds, large rivers, and saltwater near shore, where it feeds mostly on mollusks and crustaceans, a change from its usual summer diet of aquatic insects.
The Bufflehead is Climate Endangered, with a projected loss of 59 percent of its breeding habitat. Because they rely on trees for nesting, a lack of nesting sites make northern adaptation above the tree line, where the climate may be otherwise suitable, challenging.