Lophodytes cucullatushooded merganser

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.