Any bird of the genus
Mergus (
Merganser), and allied genera of the subfamily
Merginae. They are allied to the ducks, but have a sharply serrated bill, eat fish, and dive for food. Also called
fish duck. [
1913 Webster]
"
The red-breasted merganser (Merganser serrator) inhabits both hemispheres. It is called also sawbill, harle, and sheldrake. The American merganser (Merganser Americanus.) and the hooded merganser (Lophodytes cucullatus) are well-known species."
[
1913 Webster]