Three uncommon, small ducks came into view, gliding effortlessly on the glassy morning water in the Bay Farm lagoon: Hooded Mergansers. What a treat! A few years ago, my birding friend and I saw 14 of them together on a local outing. They’re seen during winter in Alameda, fishing in the lagoons, estuary, and less often in the Bay. You’ll recognize them with their shaggy-looking brown head, long, thin beak, and brown bodies for females and juveniles. The males, in their breeding plumage right now as spring approaches, have striking black and white heads with a special display feature. When they want to impress, they fan out their long head feathers into a spectacular white mohawk, edged in dark feathers. Their chestnut flanks and a distinctive white chest slashed with a black and white side pattern make them very beautiful.

This is the smallest of the three mergansers found in North America and the sole merganser species found only in North America (the other merganser species can be found on other continents). Their scientific name means “crested diver.” The Hooded Mergansers in our area are winter migrants. They arrive late in the fall and are among the first to leave for nesting grounds in the spring. They will leave our area soon for more northern and northeastern streams, rivers, ponds and lakes in forested areas, even into Canada. They prefer freshwater habitats, but during winter they will use coastal bays and estuaries, such as we have in Alameda. There are resident populations in northern Oregon and Washington on the West Coast and a larger resident population from the Midwest to the East Coast. The eastern migratory populations winter in Texas, Florida and into the Caribbean and northeastern Mexico then presumably migrate north to Canada.  

Hooded Mergansers are well adapted to fishing with their streamlined body shape and ability to see well underwater. Their beaks have fine serrations along the edges that help them grab and hold slippery fish, their primary food. They’ll also eat crabs and crayfish. They can live 11-13 years. They’re usually seen in pairs or small groups in winter, though they may roost in larger groups at night. They have a soft croaking or grunting call.

Male and female Hooded Mergansers are monogamous during the breeding season. They use tree cavities four to 15 feet off the ground and nest boxes installed for Wood Ducks. Females lay seven to 15 white eggs with very thick shells. Females will sometimes lay their eggs in other Hooded Merganser nests as well as in Wood Duck and other nests. Once the eggs are laid, the males leave the female to tend to the nest and young. Incubation lasts about one month. When the ducklings hatch the female will leave the nest and wait, calling below for the hatchlings to jump out of the nest to the ground. The babies are precocial: fully feathered, mobile and able to search for their own food right away. They eat insects and small fish. The females stay with the young birds for the first couple of weeks, protecting them and keeping them warm at night. Hooded Merganser young are “flight ready” and fledge when they're about 70 days old. 

I hope you’ll get out to enjoy a Hooded Merganser sighting while they’re still here! You can join a free, guided bird walk through Golden Gate Audubon by going to the website: www.goldengateaudubon.org.

Sharol Nelson-Embry is a Board Member with the Golden Gate Audubon Society and co-chairs the Friends of the Alameda Reserve. She retired from the East Bay Regional Park District as Supervising Naturalist at the Doug Siden Visitor Center at Crab Cove, Crown Memorial State Beach. She currently has an online chocolate tasting business featuring “Bird-friendly” chocolates at www.cocoacase.com.