Largest sawbill. Male: white to pinkish white plumage with black back and dark green head. Female with grey body and brown head. Sharp division between brown head and whitish breast, together with contrasting white chin, distinguishes it from female Red-breasted Merganser. Both sexes with hook at tip of bill, dense crest and swollen base of bill. Wing-bars all white. Flight silhouette more diver-like than duck-like.

Male: Mostly heard when courting. A twanging, disyllabic "whip-ooooo", first syllable ascending and second whistle-like and rapidly falling. Female: A coarse "ahrrr ahrrrr", or a raspy drawn "ah-ahrrrrrr ah-ahrrrrr", slightly rising, then falling in pitch. Also various cackling sounds.

Display-call male:

Wikipedia: map (se also Xeno-canto below)

Birdlife ecology

Observation.org Latest observations

Video IBC

Image search Flickr NB! May give other species

Sound search at Xeno-canto

Featherbase

Sounds:Recorded by Paul Driver,http://www.xeno-canto.org ,CC license