With exotic looks and sleek moves, these diving ducks are more than what their name suggests. Common Mergansers are winter residents, common migrants, and accidental summer tourists. Slightly larger than a mallard, yet smaller than a Canada goose, they are the largest mergansers in North America.
These long-bodied birds are uncommonly beautiful. Females sport a warm auburn, shaggy crest on their heads. The look is spiky and stunning against blue waters and sky. Males have a slick green head and white body. Both have orange bills. What they gain in looks they lack in taste. Common Mergansers are not favored by hunters as a game bird.
Common Mergansers journey down from breeding grounds in Canada and attract gulls and sometimes bald eagles along the way, trying to snag some of their prey.
You can see them on large, open waters in winter; floating, fishing, loafing, and sleeping.
Common Mergansers will dive completely underwater and can stay there for up to two minutes. Average dive times last around 30 seconds. When one dives, others will follow. Swimming is aided by powerful webbed feet.
They fish by sight and will scrape through sediment and stones looking for a catch. Their long bills have serrated edges perfect for grabbing fish. On the winter menu are trout, sculpin, suckers, and shad.
Common Mergansers travel in large flocks, and with the exception of a hoarse alarm call, are mostly silent. Cornell describes their wing sounds as hollow and rushing in flight.
Like other diving ducks, they run along the water to take off and skid along the surface for landing.
The North American Breeding Survey notes a two percent yearly decline in Common Mergansers from 1966-2014 for 65 percent overall. They have a low conservation concern rating, but since they are at the top of the food chain are considered an indicator of environmental health.
Discover more about Common Mergansers.