The Common Merganser is a large duck that is found almost anywhere north of the equator. It inhabits fresh water lakes and rivers in the summer, usually in or near woodlands, and in winter freshwater rivers and open water. This underwater hunter’s diet consists mainly of fish. Below the surface, it has expert swimming abilities in chasing down minnow sized fish.The bill has a tooth like edge that enables the bird to hang on to its prey. Mergansers are very sociable and band together in small groups. The drakes in breeding plumage are easily distinguished white breast and flanks, the head black with an iridescent green gloss, the rump and tail grey, black back with a coral-red bill. The females have a rusty head with a ragged crest, white chin, and white secondary feathers on the wing.
The Merganser nests primarily in tree cavities, hollow logs, on the ground among bushes and in rock piles. The eggs are incubated by the female only as the males abandon their mates shortly after incubation begins.In North America they winter southern California, Florida and northern Mexico and the Gulf Coast.