
Photo: (c) Thomas Galewski, some rights reserved (CC BY) · CC-BY
Mergus serrator
Rare visitor: recorded only occasionally in this country
Diet
Fish and aquatic invertebrates
Habitat
Coasts, estuaries and northern lakes
Size
51–62cm
The Red-breasted Merganser is a slim fish-eating duck with a long, narrow red bill and a conspicuously shaggy crest. Breeding males show a dark green head, white neck collar, rusty spotted breast and grey flanks. Females are grey-bodied with warm reddish-brown heads, closely resembling female Common Mergansers but appearing slimmer and showing less sharply divided head and neck colours (Wikipedia, general species account).
This merganser breeds around northern lakes, rivers and sheltered coasts, then winters mainly on estuaries and marine bays. It dives after small fish and aquatic invertebrates and may form coordinated feeding lines that drive prey together. The female nests on the ground under vegetation or among rocks rather than normally using tree cavities. Migrants occur around Japanese coasts and larger inland waters (Wikipedia, general species account).