The Bufflehead is a small duck that nests in tree cavities and dives for food. Males and females have different plumage.
In breeding plumage, the male is black and white with a large white patch behind the head. The female is gray-brown with a small white cheek patch.
Bufflehead nests can occur in trees close to a forest edge. Among 100 active natural cavities in western Canada, the mean distance from the forest edge was about 3.5 m. They averaged about 37 m from water and 6.6 m above the ground. Nesting females occupied cavities well above ground level.
The cavities examined in 1997–1999 had entrance heights and widths averaging about 9 cm. About four-fifths occurred in aspen, with other trees including conifers. Buffleheads also used nest boxes. Mean egg counts were similar: 8.4 in boxes and 8.5 in natural cavities. Behind the small entrances, females incubated clusters of eggs.
An extinction-risk assessment has not been added yet.
Ontario’s habitat-conservation guide describes Buffleheads nesting in tree cavities in wetlands, along shorelines and sometimes in adjacent woods. For waterfowl conservation, it recommends protecting substantial areas with many small and medium-sized ponds. Retaining nesting trees together with waters that provide food and cover for adults and young is a conservation priority.