The bufflehead, a small diving duck, is recognized by its disproportionately large, rounded head. Males showcase a striking black and white plumage, featuring an iridescent green and purple sheen on their heads and a prominent white patch behind the eye. Females exhibit a more subdued gray-brown coloration with a distinct white patch on their cheek. Measuring around 13 to 16 inches in length and weighing about a pound, the bufflehead is the smallest diving duck in North America. Unlike many ducks, they tend to appear in pairs or small groups rather than large flocks.
Breeding Locations and Environment
Bufflehead ducks primarily establish their breeding grounds across western and central Canada and Alaska, with some populations extending into the northwestern United States. They favor environments within the boreal forest or taiga habitat, specifically seeking out wooded lakes and ponds. These ducks nest almost exclusively in tree cavities, commonly utilizing abandoned holes created by Northern Flickers or, less frequently, Pileated Woodpeckers.
The availability of these specific tree cavities is a limiting factor for their breeding range, as buffleheads are uniquely small enough to fit into flicker holes, which larger ducks cannot use. These nest sites are typically located close to water bodies, as ducklings leave the nest within one to two days of hatching to follow their mother to water. The female lines the chosen cavity with her own down feathers, and a single clutch usually consists of 8 to 10 eggs, which incubate for about a month.
Wintering Locations and Environment
As winter approaches, bufflehead ducks undertake extensive migrations, spreading across the North American coastlines, including both the Pacific and Atlantic coasts from Alaska to Mexico and Newfoundland to Florida. They also inhabit inland freshwater bodies throughout much of the United States and parts of Mexico, including the Great Lakes region. During this non-breeding season, they prefer shallow, sheltered aquatic environments such as saltwater bays, estuaries, coastal lagoons, and large inland lakes and slow-moving rivers. Their preference for shallow waters stems from their feeding strategy, as they dive for aquatic invertebrates like crustaceans, mollusks, and insects. Their diet adapts to the available food sources, consuming more crustaceans and mollusks in saltwater environments, while still eating aquatic insects on freshwater.
Seasonal Journeys
They are among the last waterfowl to depart their breeding territories in the fall, and are known for their punctual arrival on wintering grounds. Fall migration generally begins in October, while spring migration is more protracted, occurring from late March to early May as they await the thawing of northern waters. These ducks typically migrate at night in small flocks. Their migratory routes often follow established North American flyways, with populations breeding west of the Rockies generally migrating to the Pacific Coast, and those from central Canada moving east or south. Some populations, such as those from Alberta, may disperse to both the Pacific and Atlantic coasts, as well as the Gulf Coast.