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Aythya americanaredhead

By Emily Hoak

Geographic Range

The Aythya americana breeding range extends from southern Canada to the northern United States (Washington to Maine). Many breed in the Prairie Pothole region of the northern Great Plains of North America. There are also some breeding populations in central Alaska. In September, these ducks migrate to winter in northern and central Mexico, and from California to the Gulf and Atlantic Coast. A large portion of redheads winter in Florida and Mexico. (Baldassarre and Bolen, 1994; Bellrose, 1976; Johnsgard, 1992)

Habitat

Aythya americana habitat includes shallow freshwater lakes, ponds, and marshes. The body of water needs to be at least 28 inches deep so that the ducks can dive. The Prairie Pothole region provides a perfect area for breeding due to the fact that the potholes fill up with water from melting snow and rain to provide temporary, seasonal, deposits of freshwater. Marshes also provide an area rich with aquatic plants and vegetation cover to act as protection. The ducks may be found on brackish and coastal bays and lakes.

(Baldassarre and Bolden, 1994; Johnsgard, 1992)

  • Aquatic Biomes
  • lakes and ponds

Physical Description

Males of this species are characterized by a copper-colored head and orange-yellow eyes. The back and flanks are greyish in color, the chest and tail is blackish, the breast is white, and the belly is a whitish color marked with dusty undertones. The wings are grey with slight flecks of white. The feet are bluish grey in color. When the male duck molts in June, the blackish color become more brown, and the reddish head is not as vibrant. By November, darker winter feathers have grown in.

Females do not have colors as vibrant as male coloration. The head of a female is a yellowish brown that is a bit darker on the crown, and she has a slight pale ring around her brown eyes. Her body and tail is mostly dark greyish brown and her belly is whitish fading into greyish brown. Her wings are also a brownish grey color. Her feet are a bluish color, although a little duller than that of the male.

Both the male and the female of this species have a pale blue bill with a white ring around the black tip. It is about .5 inches long. Again, the female's coloring is not as dark.

The juvenile duck's first plumage resemble a mottled version of the female. As the duckling matures, the male becomes darker than the female and they begin to have the coloring of the adults.

Mass - Males: 2.1 to 3.2 pounds, average 2.44 pounds

Females: 1.5 to 2.9 pounds, average 2.14 pounds

Length - Males: 18.1 to 21.7 inches, average 20.0 inches

Females: 18.0 to 20.5 inches, average 19.0 inches

Wingspan - Males: average 9.16 inches

Females: average 8.79 inches

(Bellrose, 1976; Kortright, 1942; Phillips and Lincoln, 1930)

  • Range mass
    680 to 1450 g
    23.96 to 51.10 oz
  • Range length
    457 to 550 mm
    17.99 to 21.65 in
  • Average wingspan
    228 mm
    8.98 in

Development

After an incubation period of 24-28 days, the eggs of the Redhead hatch. The ducklings remain in the nest for 3-18 hours after hatching so that their down can dry. At 56 days, the juvenile can be seen flapping accross the water, and at 70 to 84 days the ducks are learning to fly. Some ducks can sexually reproduce at a year, but more time is usually needed.

(Bellrose, 1976)

Reproduction

During courtship the females take the lead. The female will stand up tall and jerk her head up and down, and then hold it erect. The male she is after will also stand erect and twirl around, showing his backside to her. She may playfully nip at him, or while swimming, dash off and intersect him in his path.

If a female is focusing her attention on more than one male at a time, the males attempt to drive each other away.

Redheads tend to pair in late winter, but courtship behavior can be seen up into the month of April. This is the month where peak pair formation occurs. The males desert the females once incubation begins.

(Bellrose, 1976; Kortright, 1942)

Redheads tend to begin their breeding season in late April to early June. When a large group of breeding Redheads were studied, it was found that only half of the pairs were breeding. Apparently not all Redhead hens attempt to breed. These non-breeding hens are probably primarily yearlings.

Redheads begin to nest in the midsummer in marshes and potholes of the prairies. Nest sites may be located over water via the support of dense vegetation, on islands, or dry land. If the nest is on land, water must be nearby. Their first choice is to structure the nest using hardstem bulrush followed by cattails. The nest is deeply hollowed and lined with a thick layer of down.

Redheads exhibit interesting egg-laying strategies. Three behaviors are described: normal, semiparasitic, and parasitic. Normal behavior is when the hen lays and incubates her own eggs. Semiparasitic entails normal behavior and laying eggs in other nests. Parasitic is where the hen lays all of her eggs in another duck's nest. Often, the parasitic hen will lay her eggs in another duck's nest after incubation has occurred. This means that the parasitic female's eggs will probably not hatch because they are off schedule from the other eggs. The unhatched eggs are wasted. Sometimes the parasitic female will lay her eggs in the nest of another species.

A female lays, on average, one egg a day, but will skip a few days before the clutch is complete. On average, only 52% of nests have some eggs that have hatched.

(Bellrose, 1976; Kortright, 1942)

  • Breeding season
    late April to early June
  • Range eggs per season
    9 to 11
  • Average eggs per season
    13
    AnAge
  • Range time to hatching
    24 to 28 days
  • Range fledging age
    55 to 75 days
  • Range age at sexual or reproductive maturity (female)
    1 (low) years
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Range age at sexual or reproductive maturity (male)
    1 (low) years
  • Average age at sexual or reproductive maturity (male)
    1 years

Right before the eggs hatch, the female emits a low kuk-kuk-kuk sound. This sound is extremely important because it imprints on the ducklings to follow her when they are hatched. Redheads are known for their early desertion of their young, and the mother leaves the juveniles when they are able to fly.

(Bellrose, 1976)

Lifespan/Longevity

Disease greatly affects the longevity of the Redhead. Duck Virus Enteritis (DVE), caused by the herpes virus, can cause hemorrhaging and death within two weeks of exposure. If the duck survives, it may become a carrier of the disease. Redheads are moderately susceptible to this. Another disease that affects the ducks is avian botulism. The disease affects the peripheral nerves, and one characteristic is a drooping neck. Maggots feed on the birds that died of avian botulism, concentrating toxin inside themselves. When a Redhead eats the maggot, the toxin is ingested and the cycle starts all over again. Lead posioning is also a major cause of death in waterfowl. The duck eats the lead pellets that have been discarded from shotgun shells. The duck will become weaker over time until it starves to death. Redheads are very susceptible to this because they are bottom-feeders. Also, one of the greatest threats to the Redhead is hunting.

The oldest known wild Redhead lived 22 years 7 months after banding.

(Baldassarre and Bolen, 1994; USGS Bird Banding Laboratory, 2003)

Behavior

Redheads are excellent divers and use this trait for obtaining food.

Redheads are migratory. By September, the fall migration south has begun. In March, the birds fly back north to begin their breeding season. The ducks migrate in V-formations at great speeds. They will fly for long distances in the morning and evening. Their flight may seem a bit erratic because they beat their wings so rapidly. When they spot a particular area to land, they may circle it and gradually make their descent, ending with a splashing into the water. Another way they land is by making a great zigzag pattern. The flock becomes a muddled mass of birds until their wings become motionless and they glide into the water. When they rise out of the water, their flight is confusing and looks hurried.

The ducks may be found singly, in pairs, or in flocks of 5 to 15. At popular wintering areas, they can be found by the hundreds and sometimes thousands.

The ducks demonstrate homing behavior, but may pioneer a new breeding area.

When the ducks have settled in deep water, they may suddenly rise into the air for no apparent reason or any source of commotion.

(Bellrose, 1976, Kortright, 1942)

Communication and Perception

Food Habits

Redhead diet is mainly composed of vegetable matter. It dives to the bottom of the body of water to feed on aquatic plants and mollusks and dabbles on the surface of shallow marshes to locate insects. Prior to the egg-laying season the females up their animal matter intake to increase their protein levels. At this time about 77% of their diet is animal related. About half of the duckling's diet is made up of animal matter to supply the nutrients needed to grow.

Foods commonly eaten include: shoalgrass, pondweeds, muskgrass, sedges, grasses, wild celery, duckweeds, water lilies, grasshoppers, caddisflies, midges, water fleas, scuds, water boatmen and snails.

(Kortright, 1942; Baldassarre and Bolen, 1994)

  • Animal Foods
  • insects
  • mollusks
  • Plant Foods
  • leaves
  • algae

Predation

Some Redheads build their nests over the water so that terrestrial animals, like skunks, will not destroy them. Unfortunately, water poses no problem for raccoons. Terrestrial and bird predators eat the duck's eggs. Redheads also attempt to hide their nests, and this greatly reduces the risk of predation.

The female of the species has muted colors so that she will be less noticible to predators when she is incubating her clutch. The ducklings are camouflaged as well. This characteristic allows the ducks to conceal themselves from sport hunters, too.

(Bellrose, 1976)

Ecosystem Roles

Redheads have adapted parasitic egg-laying strategies, where they lay their eggs in another duck's nest.

(See Reproduction section.)

Their eggs are also part of the food web for predators.

(Bellrose, 1976)

Species Used as Host
  • other redheads
  • canvasbacks
  • mallards
  • blue-winged teals
  • cinnamon teals
  • lesser scaups
  • ruddy ducks

Economic Importance for Humans: Positive

The Redhead can be a tasty dinner for humans. Because of the Redhead's diet, it does not have the fishy flavor that other waterfowl have.

These ducks are also common in waterfowl collections because as breeders, they are fairly reliable.

(Kortright, 1942; Todd, 1979)

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

None known.

Conservation Status

In the 1970's the Redhead population took a major blow. The vegetation of the Chesapeake Bay area had been declining for years. The combination of agriculture and urban expansion affecting the turbidity of the water, excessive amounts of nutrients, pollution from agriculture, and contamination of toxins added to the disruption of the birds' habitat. As if all of these factors were not enough, Hurricane Agnes greatly affected run-off, thus increasing sediments and decreasing salinity. All these events had a major impact on the vegetation, the primary food source of the Redheads. They were forced to feed on other forms of vegetable life. The states of Maryland and Virginia have created preservation programs in an attempt to reverse the degredation. These programs aim to protect the wildlife and increase research in the area.

In 1908, President Theodore Roosevelt established the Malheur National Wildlife Refuge to protect breeding and migrating waterfowl. It is one of the largest freshwater marshes in the United States. A major breeding population of Redheads resides there.

Because of an overhunting problem, laws were enacted to try to limit these types of deaths.

(Baldassarre and Bolden, 1994)

Other Comments

Common names: redhead, pochard, raft duck, red-headed raft duck, American pochard, red-headed broadbill, fool duck, fiddler

(Bellrose, 1976; Phillips and Lincoln, 1930)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Emily Hoak (author), University of Michigan-Ann Arbor, Kerry Yurewicz (editor), 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.

chemical

uses smells or other chemicals to communicate

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.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

freshwater

mainly lives in water that is not salty.

internal fertilization

fertilization takes place within the female's body

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.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

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

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.

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

Baldassarre, G., E. Bolen. 1994. Waterfowl Ecology and Management. New York: John Wiley & Sons, Inc..

Bellrose, F. 1976. Ducks, Geese and Swans of North America. Harrisburg: Stackpole Books.

Johnsgard, P. 1992. Ducks in the Wild: Conserving Waterfowl and Their Habitats. New York: Prentice Hall General Reference.

Kortright, F. 1942. The Ducks, Geese and Swans of North America. Washington, D. C.: The American Wildlife Institute.

Phillips, J., F. Lincoln. 1930. American Waterfowl: Their Present Situation and the Outlook for their Future. Boston: Houghton Mifflin Company.

Todd, F. 1979. Waterfowl: Ducks, Geese & Swans fo the World. New York: Sea World Press.

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