- 15.7–19.3 in
- 23.6–26 in
- 16–31 oz
- Smaller than a Red-breasted Merganser; larger than a Bufflehead.
- Harle Couronné (French)
- Serreta capuchona (Spanish)
- Along with Wood Ducks and other cavity-nesting ducks, Hooded Mergansers often lay their eggs in other females’ nests. This is called “brood parasitism” and is similar to the practice of Brown-headed Cowbirds, except that the ducks only lay eggs in nests of their own species. Female Hooded Mergansers can lay up to about 13 eggs in a clutch, but nests have been found with up to 44 eggs in them.
- Hooded Mergansers find their prey underwater by sight. They can actually change the refractive properties of their eyes to improve their underwater vision. In addition, they have an extra eyelid, called a “nictitating membrane,” which is transparent and helps protect the eye during swimming, like a pair of goggles.
- Hooded Merganser ducklings leave their nest cavity within 24 hours of hatching. First, their mother checks the area around the nest and calls to the nestlings from ground level. From inside the nest, the little fluffballs scramble up to the entrance hole and then flutter to the ground, which may be 50 feet or more below them. In some cases they have to walk half a mile or more with their mother to the nearest body of water.
- On the bird family tree, Hooded Mergansers (genus Lophodytes) lie between goldeneyes (Bucephala) and the other North American mergansers (Mergus). They share many courtship behaviors and calls with both of those groups.
- The Hooded Merganser is the second-smallest of the six living species of mergansers (only the Smew of Eurasia is smaller) and is the only one restricted to North America.
- The oldest Hooded Merganser on record was 14 years, 6 months old.
Hooded Mergansers breed in forested wetlands throughout the eastern half of North America and the Pacific Northwest, and may also nest in treeless wetlands where people have put up nest boxes. They are most common in forests around the Great Lakes. Their habitat ranges from spruce-fir forest in the Northwest to pine-hardwood forest and cottonwood-elder riparian forest in the Midwest, to oak-cypress-tupelo forest in the Southeast. Families of newly hatched ducklings forage in shallow water such as marshes, small lakes, ponds, beaver wetlands, swamps, and forested rivers—and rest on exposed rocks, logs, or sandbars. They winter in these habitats as well as on shallow freshwater and brackish bays, estuaries, and tidal creeks, where they often concentrate along the edge of ice. During migration they stop in a wider range of habitats, including open waters of rivers and lakes, brackish coastal bays, tidal creeks, and seasonally flooded forest.
Hooded Mergansers eat small fish, aquatic insects, crustaceans (especially crayfish), amphibians, vegetation, and mollusks—their diet is broader than in other mergansers, which eat fish almost exclusively. Hooded Mergansers dive in clear, shallow forest ponds, rivers, and streams and locate prey by sight, with eyes that are specially adapted to seeing underwater. They propel themselves with their feet and use their slender, serrated bills to grasp their prey. Ducklings can dive for food right after leaving the nest, at one day old, though their dives are short and shallow during their first week. They also feed by swimming with just their heads underwater.
- Clutch Size
- 5–13 eggs
- Number of Broods
- 1 broods
- Egg Length
- 1.7–2.4 in
- Egg Width
- 1.5–2.1 in
- Incubation Period
- 26–41 days
- Nestling Period
- 1 days
- Egg Description
- White, nearly spherical, and unusually thick shelled.
- Condition at Hatching
- Well-developed and downy, with brown backs, yellowish or reddish cheeks, white underparts, and grayish spots on wings and tail.
The female makes a shallow bowl in the material already present in the cavity, gradually adding down from her belly after she starts laying eggs.
The female chooses the nest site, and may start scouting for next year’s tree cavity at the end of each breeding season. Nest cavities can be in live or dead trees and are usually close to water. Cavities are typically 10–50 feet off the ground, up to about 90 feet. Hooded Mergansers nest readily in boxes, preferring those with wood shavings or nest material from previous uses. They prefer cavities with 3–5 inch openings.
Unlike dabbling ducks, Hooded Mergansers swim low in the water. Their legs are far back on their bodies, which helps in diving but makes them awkward on land. They take flight by running across the water, flying with fast wingbeats and never gliding until they are about to land (by skidding to a stop on the water). Hooded Mergansers are usually in pairs or small groups of up to 40 birds. They court in groups of one or more females and several males. The males raise their crests, expanding the white patch, often while shaking their heads. Their most elaborate display is head-throwing, in which they jerk their heads backwards to touch their backs, with crests raised, while giving a froglike croak. Females court by bobbing their heads and giving a hoarse gack. Once a female begins incubating eggs her mate abandons her, and it’s not known if they reunite the following season. Incubating females may use a broken-wing display to protect eggs or nestlings from raccoons, mink, black rat snakes, black bears, pine martens, European Starlings, Northern Flickers, Red-headed Woodpeckers, and Red-bellied Woodpeckers.
Hooded Mergansers are fairly common and their populations are stable and have possibly been increasing since 1966, according to the North American Breeding Bird Survey. They are found in many parts of the U.S. in Canada throughout the year. In the early twentieth century, these birds were overhunted, but hunting pressure has declined markedly since then: hunters take about 95,000 Hooded Mergansers per year in the U.S., out of roughly 15 million ducks shot each year. Even before the twentieth century, humans cleared and altered many forests where Hooded Mergansers nest, in the process reducing or displacing breeding birds from regions of their original range. As with all birds that nest in tree holes, dead trees are important habitat components and landowners can improve Hooded Merganser habitat by leaving dead trees standing on their property. In addition, Hooded Mergansers take readily to nest boxes of the appropriate size, and programs in Missouri, Maine, Iowa, and Oregon have helped local populations increase.
- Dugger, B. D., K. M. Dugger and L. H. Fredrickson. 2009. Hooded Merganser (Lophodytes cucullatus). In The Birds of North America, No. 98 (A. Poole, ed.). The Birds of North America Online, Ithaca, New York.
- Raftovich, R.V., K.A. Wilkins, S.S. Williams, H.L. Spriggs, and K.D. Richkus. 2011. Migratory bird hunting activity and harvest during the 2009 and 2010 hunting seasons [PDF]. U.S. Fish and Wildlife Service, Laurel, MD.
- U.S. Fish and Wildlife Service. 2012. Harvest Information Program.
- USGS Patuxent Wildlife Research Center. 2011. Longevity Records of North American Birds.
- USGS Patuxent Wildlife Research Center. 2012. North American Breeding Bird Survey 1966–2010 analysis.
Resident to medium-distance migrant. In eastern North America, many Hooded Mergansers move south and southwest in winter, but some actually migrate north to spend winters in the Great Lakes and southern Canada. Most of the Hooded Mergansers that breed in the upper Midwest migrate along the Mississippi River. Hooded Mergansers breeding west of the Rockies migrate west and south toward the Pacific. Hooded Mergansers are late fall migrants, sometimes moving just ahead of winter ice. In spring they arrive early at breeding grounds, within a few days of the ice melting.
Hooded Mergansers will nest in appropriately sized boxes, particularly if you live near wetlands. You can get construction plans for building the right kind of nest box for many species from our NestWatch project. If your box does not have nest material from a previous resident, you can add wood shavings to entice a new resident.
Find This Bird
Hooded Mergansers are fairly common on small ponds and streams across their breeding range. In fall through spring, head to unfrozen lakes or shallow, protected saltwater bays and look for them mixed in flocks with other small divers like Bufflehead and Ruddy Ducks. Pay attention for flying ducks too—a fast series of truncated whistles from high overhead may signal the rapid wingbeats of a commuting merganser.