Mergansers are not like the typical duck. Instead of the classic duck bill, they have a long, thin bill with tiny teeth-like serrations used for capturing fish and other live prey. Mergansers are not popular with hunters as their meat has an unpleasant fishy test.
What you should know
1. Males in breeding plumage are distinctive.
2. First spring males and males in eclipse plumage resemble females.
Female Common and Red-breasted Mergansers are similar and can be confused.
Select a species:
The first image is a female Common Merganser. White chin sharply marked from the rest of the face color. First spring males similar, may show dark markings on the chin and a dark ring on the neck, separating the brown neck from the gray chest.
The second image is a female Red-breasted Merganser. Some femals may show more white on the chin and neck but the white will be more diffused, not sharply marked as on the common. Compare the difference in the shape of the bill. The bill of the Common Mergansers is heavier and wider at the base. The bill of the Red-breasted is thinner.