The Bufflehead (Bucephala albeola) is North America’s smallest diving duck, recognizable by the male’s distinctive head patch and compact body. These highly migratory ducks rely entirely on aquatic environments for their diet. Their survival depends on specialized diving techniques to forage efficiently beneath the surface. Understanding their diet reveals much about their life cycle and the habitats they use throughout the year.
Primary Diet: Aquatic Invertebrates
The Bufflehead’s diet consists overwhelmingly of animal matter, primarily aquatic invertebrates. On freshwater breeding grounds, they focus heavily on the larval and pupal stages of insects. Specific prey includes the larvae of midges, damselflies, dragonflies, caddisflies, and mayflies, which provide the energy necessary for reproduction.
Small crustaceans, such as amphipods, are a staple in both freshwater and saltwater habitats. Mollusks, including small snails and clams, also form a significant component of the diet, especially during winter. Prey is typically swallowed whole while the duck is still submerged.
The Bufflehead consumes a minor amount of plant matter, mainly seeds from aquatic plants like pondweeds and bulrushes, during the fall and winter. However, the duck’s nutritional demands are almost entirely met by the protein and fat content of its invertebrate prey.
Specialized Feeding Techniques
The Bufflehead is a true diving duck, obtaining food by fully submerging, unlike surface-feeding dabbling ducks. They propel themselves underwater using powerful, webbed feet set far back on the body. This adaptation enhances their aquatic mobility, allowing them to be fast and agile swimmers beneath the surface.
A typical dive lasts 12 to 25 seconds, after which the duck quickly resurfaces to breathe before diving again. To aid submerging, they compress their feathers to squeeze out trapped air, reducing buoyancy. They forage using sight, targeting prey in clear, shallow waters, usually preferring depths of less than three meters.
Their hunting strategy often involves small flocks diving concurrently, though one bird may remain on the surface as a sentinel. Buffleheads are efficient hunters, often consuming captured prey before returning to the surface. This ability to process food underwater maximizes their foraging time.
Winter vs. Breeding Season Diet
The Bufflehead’s diet changes significantly with the seasons, driven by location and nutritional requirements. During the breeding season on inland freshwater lakes, the female requires a high-protein diet to support egg production. This need is met by the abundance of aquatic insect larvae, which provide a concentrated source of protein.
When the ducks migrate to their wintering grounds, often along coastal saltwater environments, their diet shifts to reflect local availability. The winter diet incorporates more marine organisms, moving beyond insect larvae. They consume a wider range of crustaceans, such as shrimp and crabs, and mollusks like mussels and marine snails.