At 40-49 cm, the Hooded Merganser is the smallest North American merganser. Exact weights have not been documented. Like all mergansers, it has a long, narrow, serrated bill. It has a brownish-black back and wings, with a white underside. The male has a black head with a white, fan-shaped crest, which is bordered in black. The males iris is bright yellow, while the iris of females and immature males is duller brown.
Range mass: 540 to 680 g.
Range length: 40 to 49 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes colored or patterned differently; male more colorful
The eggs of the Hooded Merganser are almost spherical and have a disproportionately thick shell.
Perception Channels: visual ; tactile ; acoustic ; chemical
At the turn of the century, Hooded Mergansers were largely overhunted. Today, however, they are not a prized sport species. Habitat degradation is now a more pressing concern for their conservation. River channalization, deforestation, and agricultural practices have caused an increase in loose sediment and turbidity, reducing the available habitat for the Hooded Merganser. Also, acid rain has the potential to harm the species, because a low pH can cause a significant reduction in aquatic invertebrates. A diminished food supply would reduce the growth of young ducklings. There is no informaton on the exact population size, and the Hooded Merganser has no special conservation status. In the future, care must be taken to preserve the cavity producing trees and forests which these birds depend on.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse effects of hooded mergansers on humans.
Hooded Mergansers are still hunted occasionally for sport. Aprooximately 18, 000 are harvested annually in the U.S. and Canada combined. They are also used for various scientific studies in the wild, because they will nest in artifical nestboxes.
Positive Impacts: body parts are source of valuable material; research and education
Hooded Mergansers feed in clear aquatic habitats, such as forested ponds, rivers, streams, and flooded forests. Their primary foods include aquatic insects, fish, and crustaceans.
Animal Foods: fish; insects; aquatic crustaceans
Primary Diet: carnivore (Piscivore , Insectivore , Eats non-insect arthropods)
The Hooded Merganser breeds throughout the Pacific Northwest of the United States, across southern Canada, and east of the Mississippi. It is largely concentrated in forested regions around the Great Lakes. Wintering ranges include an area along the Pacific Coast of California, and a second area of coastal habitats from Delaware through Texas.
Biogeographic Regions: nearctic (Native )
The Hooded Merganser nests in forested wetlands throughout its range. Some records show nesting in man-made boxes on grasslands and in nonforested wetlands. The kind of forest used for nesting varies from spruce/fur to cottonwood/elder and oak/cypress/tupelo, depending on the geographic location. In the winter they seek out shallow, freshwater and brackish bays, estuaries, and tidal creeks and ponds.
Habitat Regions: temperate ; terrestrial ; freshwater
Terrestrial Biomes: forest
Aquatic Biomes: lakes and ponds; rivers and streams
Wetlands: marsh ; swamp
Other Habitat Features: riparian
Average lifespan
Status: wild: 138 months.
Pair formation has been observed from November through January. Only monogamous pairs have been documented.
Mating System: monogamous
Females select the nest site, which is usually a cavity in a dead or live tree. Nest boxes, along with already built and abandoned nest sites, are preferred. Cavities are usually 4-15 feet off the ground. Between 7 and 15 eggs are laid shortly after the nest is completed, from late February through early June, depending on latitude, although most breeding occurs in March and April. Incubation begins after all the eggs have been laid. The male abandons the female shortly after this point. The female incubates for nearly one month, during which time she loses 8-16% of her body weight. After the ducklings hatch they usually leave the nest within about 24 hours.
Breeding interval: Hooded mergansers have one brood each year.
Breeding season: Hooded mergansers breed from late February into June, depending on latitude. Although most breeding occurs in March and April.
Range eggs per season: 7 to 15.
Range time to hatching: 26 to 41 days.
Average time to independence: 5 weeks.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average eggs per season: 11.
Females brood eggs in the nest and care for young after hatching. Males leave the female soon after egg incubation begins. Young hooded mergansers leave their nest within 24 hours of hatching and are able to feed and dive immediately upon emergence from the nest. There is little information on parental care after hatching. One female abandoned her brood 5 weeks after hatching.
Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)
A medium-sized (16-19 inches) duck, the male Hooded Merganser is most easily identified by its black head and body, rufous flanks, thin bill, and conspicuous white crest. Females are duller brownish-gray overall with a smaller brown crest. At a distance, the male of this species may be confused with the male Bufflehead (Bucephala albeola), which may be distinguished by its greenish head and white body. Duck hunters often call mergansers “saw-bills” in reference to their long, thin, serrated bills. The Hooded Merganser breeds across a large part of the eastern United States and southern Canada south to the Gulf coast and west to the edge of the Great Plains. Another breeding population exists in the Pacific Northwest. In winter, this species migrates away from northern and higher-altitude areas, and may be found along the Pacific coast from Alaska to California, in the eastern and southeastern U.S., and at scattered locations in the western U.S. Hooded Mergansers breed in lakes and ponds surrounded by woodland. Like a couple other smaller species of ducks, this species nests in tree cavities, often those left over from woodpecker nest sites. In winter, Hooded Mergansers may be found in freshwater or saltwater on rivers, marshes, estuaries, and bays. This species primarily eats small aquatic animals such as crustaceans, fish, and insects. One of several species of “diving ducks” in North America, Hooded Mergansers may be observed submerging themselves to feed in the water or on the bottom. In winter, they may also be observed in small flocks on slow-moving bodies of water. Like other mergansers, the Hooded Merganser undertakes swift, straight flights between bodies of water or on migration. This species is primarily active during the day.
A medium-sized (16-19 inches) duck, the male Hooded Merganser is most easily identified by its black head and body, rufous flanks, thin bill, and conspicuous white crest. Females are duller brownish-gray overall with a smaller brown crest. At a distance, the male of this species may be confused with the male Bufflehead (Bucephala albeola), which may be distinguished by its greenish head and white body. Duck hunters often call mergansers “saw-bills” in reference to their long, thin, serrated bills. The Hooded Merganser breeds across a large part of the eastern United States and southern Canada south to the Gulf coast and west to the edge of the Great Plains. Another breeding population exists in the Pacific Northwest. In winter, this species migrates away from northern and higher-altitude areas, and may be found along the Pacific coast from Alaska to California, in the eastern and southeastern U.S., and at scattered locations in the western U.S. Hooded Mergansers breed in lakes and ponds surrounded by woodland. Like a couple other smaller species of ducks, this species nests in tree cavities, often those left over from woodpecker nest sites. In winter, Hooded Mergansers may be found in freshwater or saltwater on rivers, marshes, estuaries, and bays. This species primarily eats small aquatic animals such as crustaceans, fish, and insects. One of several species of “diving ducks” in North America, Hooded Mergansers may be observed submerging themselves to feed in the water or on the bottom. In winter, they may also be observed in small flocks on slow-moving bodies of water. Like other mergansers, the Hooded Merganser undertakes swift, straight flights between bodies of water or on migration. This species is primarily active during the day.
The hooded merganser (Lophodytes cucullatus) is a species of fish-eating duck in the subfamily Anatinae. It is the only extant species in the genus Lophodytes. The genus name derives from the Greek language: lophos meaning 'crest', and dutes meaning 'diver'.[2] The bird is striking in appearance; both sexes have crests that they can raise or lower, and the breeding plumage of the male is handsomely patterned and coloured. The hooded merganser has a sawbill but is not classified as a typical merganser.
Hooded mergansers are the second-smallest species of merganser, with only the smew of Europe and Asia being smaller, and it also is the only merganser whose native habitat is restricted to North America.
A species of fossil merganser from the Late Pleistocene of Vero Beach, Florida, was described as Querquedula floridana (a genus now included in Anas), but upon reexamination turned out to be a species closely related to the hooded merganser; it is now named Lophodytes floridanus, but the exact relationship between this bird and the modern species is unknown.
The hooded merganser was one of the many bird species originally described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae, where it was given the binomial name Mergus cucullatus.[3]
The hooded merganser is a sexually dimorphic species. The adult female has a greyish-brown body, with a narrow white patch over the lower breast and belly. She has a light reddish-brown crest extending from the back of the head. During the nonbreeding season the male looks similar to the female, except that his eyes are yellow and the female's eyes are brown.
In breeding plumage the dorsal areas and the head, neck and breast of the mature male are mainly black with white markings; there are large white patches on either side of the crest, and they are particularly conspicuous when he raises his crest during courtship. His lower flanks are a rich reddish-brown or chestnut in colour, and the breast and undersides are more or less white, extending into white stripes across the crop and breast.
In both sexes there are narrow white stripes along the tertial wing feathers; when the bird is in repose they have the appearance of longitudinal white stripes along the bird's lower back, if they are visible.[4]
First-winter birds differ from adult females in appearance in that they have a grey-brown neck and upper parts; the upper parts of adult females are much darker — nearly black. Furthermore, the young birds have narrower white edges to their tertial feathers than adults do. Females of all ages are dark-eyed, whereas in males the eyes become pale during their first winter.[5]
Measurements:[6]
Hooded mergansers are short-distance migrants, and they winter in the United States in regions where winter temperatures allow for ice-free conditions on ponds, lakes and rivers. They have two major year-round ranges. One is in the eastern United States from the southern Canada–US border along the Atlantic Coast to the Gulf Coast in the region of the Mississippi delta. A smaller year-round range extends from Washington state and southern British Columbia to northern Idaho. They also breed to some extent in regions from Missouri to southern Canada and from Nova Scotia to eastern North Dakota and Saskatchewan, migrating when necessary to avoid winter conditions.[7] From 1966 - 2015, the hooded merganser experienced a>1.5% yearly population increase throughout its breeding range.[8]
For preference the hooded merganser lives on small bodies of water such as ponds and small estuaries where there is ample emergent aquatic vegetation, but it also inhabits larger wetlands, impoundments, flooded timber, and rivers. They prefer fresh water but do occur on brackish water bodies as well.[9]
Although the hooded merganser is a common species in captivity in Europe and most specimens recorded in the wild are regarded as escapes, a small number of birds have been regarded as genuinely wild vagrants. Britain's current first accepted record is a bird which was seen on North Uist in October 2000.[10] Small numbers are seen regularly in Dublin, but these are presumed to be escapes.
The hooded merganser is a diving predator that largely hunts by sight while under water. Most studies report that its diet varies according to circumstances, usually being dominated by fish (44-81%). In addition it feeds on aquatic insects (13-20% of its diet) and other aquatic invertebrates such as crabs and crayfish (22-50%).[11]
Males and females of the hooded merganser form monogamous pairs and they remain together until the female has selected a nesting cavity and completed laying her clutch. After that, the male leaves the female to incubate and care for the brood. Females will actively seek out cavities in dead trees or artificial nest boxes such as those provided for nesting wood ducks. They prefer cavities 4–15 feet off the ground. Breeding occurs anytime between the end of February and the end of June, depending on the region.
The female will lay a clutch of 7-15 eggs but only begins incubation when the last egg has been laid, thereby permitting synchronous hatching. All hatchlings are consequently of the same size, which facilitates efficient parental care. During incubation, the female may lose anywhere from 8% to 16% of her body weight.
Like most waterfowl, hooded merganser hatchlings are precocial and usually leave the nest within 24 hours after they hatch; this is about long enough to accommodate synchronous hatching. Once they leave the nest, the young are capable of diving and foraging, but remain with the female for warmth and protection.[12]
Population declines in the past have been linked with large scale deforestation. Because these waterfowl are cavity nesters, they require mature trees in which suitable nesting sites are likely to be found. It has been suggested that in recent years proper timber management is increasing available habitat successfully. One priority consideration when managing wooded habitat for cavity nesting ducks, is to maintain a sufficient population of mature trees in which suitable nesting cavities would be plentiful.[13] In addition these ducks do make use of artificial nest boxes when available.[14]
Because of their high reliance on aquatic prey, hooded mergansers are very susceptible to harm from many types of pollution, some of which are poisons that accumulate in the food organisms, directly poisoning predators high in the food chain, and some of which simply reduce the populations of their prey.[13][15][16]
The hooded merganser (Lophodytes cucullatus) is a species of fish-eating duck in the subfamily Anatinae. It is the only extant species in the genus Lophodytes. The genus name derives from the Greek language: lophos meaning 'crest', and dutes meaning 'diver'. The bird is striking in appearance; both sexes have crests that they can raise or lower, and the breeding plumage of the male is handsomely patterned and coloured. The hooded merganser has a sawbill but is not classified as a typical merganser.
Hooded mergansers are the second-smallest species of merganser, with only the smew of Europe and Asia being smaller, and it also is the only merganser whose native habitat is restricted to North America.
A species of fossil merganser from the Late Pleistocene of Vero Beach, Florida, was described as Querquedula floridana (a genus now included in Anas), but upon reexamination turned out to be a species closely related to the hooded merganser; it is now named Lophodytes floridanus, but the exact relationship between this bird and the modern species is unknown.
