Living Bird Magazine
The Red-breasted Merganser is a shaggy-headed diving duck also known as the "sawbill"; named for its thin bill with tiny serrations on it that it uses to keep hold of slippery fish. It breeds in the boreal forest on freshwater and saltwater wetlands. Males are decked out with a dark green shaggy head, a red bill and eye, and a rusty chest. Females lack the male's bright colors but also don the same messy do. It parades around coastal waters and large inland lakes in the United States and Mexico in the winter.More ID Info
The winter months are the best time to go looking for a Red-breasted Merganser, when they are fairly common along coastal waters in the United States and Mexico. Look for them in sheltered estuaries and bays swimming along in small groups or by themselves. Red-breasted Mergansers forage near the shore, so a spotting scope may not be needed to get good looks. They often sit low in the water and have a profile similar to a loon at a distance, but they have a much thinner bill. Females and nonbreeding males look like Common Mergansers, but Red-breasted Mergansers tend to use saltwater more often than Common Mergansers.