The common merganser is a fairly large and attractive duck that is frequently encountered in the Upper Delaware region. Many will recognize the deep green head of the male and tufted cinnamon head of the female. Both sexes sport long narrow bills with serrated edges that aid these diving ducks when hunting the small fish, amphibians, mollusks, crustaceans and other invertebrates they prefer.

Also called “sawbills” for this characteristic, common mergansers begin their lives by consuming aquatic insects before switching to fish when nearly two weeks old. They typically range in size from 21 to 28 inches long, with wingspans of approximately 34 inches and weights of 32 to 76 ounces. Their call is described as a low rasping croak.

Pairs are formed in late winter, with breeding occurring along forested lakes and rivers. Nesting takes place in tree cavities or nest boxes lined with down feathers collected from the female’s chest. Within a day or two of hatching, the young leave the nest and begin diving to capture their prey.