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Lophodytes cucullatushooded merganser

By Jennifer Roof

Geographic Range

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. (Dugger, et al., 1994)

Habitat

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. (Dugger, et al., 1994)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

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. (Dugger, et al., 1994)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • male more colorful
  • Range mass
    540 to 680 g
    19.03 to 23.96 oz
  • Range length
    40 to 49 cm
    15.75 to 19.29 in

Reproduction

Pair formation has been observed from November through January. Only monogamous pairs have been documented. (Dugger, et al., 1994)

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. (Dugger, et al., 1994)

  • 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
  • Average eggs per season
    11
    AnAge
  • Range time to hatching
    26 to 41 days
  • Average time to independence
    5 weeks

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. (Dugger, et al., 1994)

  • Parental Investment
  • precocial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

Behavior

Although the Hooded Merganser is mostly aquatic and awkward on land, females lead their ducklings up to 1.2 km across land from inland nests in order to reach water. Hooded Mergansers are clumsy, but quick, flyers. They take off by running on water, and they have a ceaseless and rapid wingbeat during flight. They land at high speeds and are often seen 'skiing' across the water to come to a stop. They dive well, holding their wings in close to their body and propelling themselves underwater with their feet. They have been seen gathering at roost sites in large groups during the nonbreeding season. Little is known about their territoriality during the breeding season. (Dugger, et al., 1994)

Communication and Perception

Food Habits

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. (Dugger, et al., 1994)

  • Animal Foods
  • fish
  • insects
  • aquatic crustaceans

Economic Importance for Humans: Positive

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. (Dugger, et al., 1994)

  • Positive Impacts
  • body parts are source of valuable material
  • research and education

Economic Importance for Humans: Negative

There are no known adverse effects of hooded mergansers on humans.

Conservation Status

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. (Dugger, et al., 1994)

Other Comments

The eggs of the Hooded Merganser are almost spherical and have a disproportionately thick shell. (Dugger, et al., 1994)

Contributors

Jennifer Roof (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

freshwater

mainly lives in water that is not salty.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

migratory

makes seasonal movements between breeding and wintering grounds

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

piscivore

an animal that mainly eats fish

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

visual

uses sight to communicate

young precocial

young are relatively well-developed when born

References

Dugger, B., K. Dugger, L. Frederickson. 1994. Lophodytes cucullatus. Birds of North America, 98: 1-19.

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