Mergellus albellus

Smew

Family: Anatidae · Class: Aves · Order: Anseriformes

The Smew is a small diving duck with distinctive black and white plumage. Adult males display striking white bodies with black markings around the eyes, creating a mask-like pattern, along with black lines on the back and flanks. The head shows a prominent white crest that can be raised or lowered. Males measure approximately 38-44 cm (15-17 inches) in length with a wingspan of 56-69 cm (22-27 inches). Females and juveniles are smaller and less conspicuous, with gray bodies, rusty-brown heads, and white cheeks and throat patches. Both sexes have serrated bills adapted for catching fish, and webbed feet positioned far back on the body for underwater propulsion. The Smew breeds primarily in the boreal forests of northern Europe and Asia, from Scandinavia east to Siberia. In North America, this species is considered a rare vagrant, with occasional sightings along both Atlantic and Pacific coasts. California records are extremely uncommon, with documented observations primarily along the coast and in the Central Valley during winter months. Most North American occurrences involve single individuals, often associating with flocks of other diving ducks. During the breeding season, Smew inhabit forested areas near freshwater lakes, slow-moving rivers, and large ponds. They require mature trees with suitable cavities for nesting, often utilizing old woodpecker holes or natural tree hollows. Wintering habitat includes coastal bays, estuaries, large lakes, and reservoirs where fish populations are abundant. The species prefers relatively clear water that allows visual hunting for prey. Smew are piscivorous, feeding primarily on small fish including minnows, sticklebacks, and young perch. They also consume aquatic invertebrates, crustaceans, and occasionally amphibian larvae. Foraging occurs through diving, with birds submerging completely and pursuing prey underwater using their feet for propulsion. Breeding occurs from May through July, with females laying 6-9 creamy-white eggs in tree cavities lined with down. Incubation lasts approximately 30 days, and ducklings fledge after 65-70 days. The species is generally silent except during breeding season when males produce soft trilling calls. The Smew is not federally listed in the United States, as it is not considered a regular component of North American avifauna. The species' global population is considered stable, though it faces localized threats from habitat loss, particularly the removal of old-growth forests containing suitable nesting cavities. Climate change may affect breeding ranges in northern latitudes, potentially altering migration patterns. In Europe and Asia, where the species is more common, conservation efforts focus on maintaining mature forest habitats near water bodies and monitoring population trends through breeding bird surveys.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.