Bucephala clangula

Geographic Range

Common goldeneyes are found throughout North America and Eurasia. They breed in higher latitudes, from Scotland, northern Europe, and Scandinavia across northern Eurasia to the Kamchatka Peninsula and throughout much of Canada from interior British Columbia to Newfoundland. They breed also in northernmost Michigan, northeastern Minnesota, northern Montana, and portions of northern New York, Vermont, and Maine. Winter ranges include coastal North America from Alaska to Baja California, Newfoundland to Florida, and the northern Gulf of Mexico, throughout inland United States except for portions of Texas, the southeast, and Arizona, and into the Sierra Madre range of Mexico and northernmost coastal Mexico. In Eurasia they are found in coastal waters from Scandinavia to the Mediterranean, Black, and Caspian Seas and from Kamchatka to Japan. They are also found in inland lakes that remain ice-free.

• Biogeographic Regions
• nearctic nearctic
  • native native
• palearctic palearctic
  • native native

• Other Geographic Terms
• holarctic holarctic

Habitat

During the breeding season, common goldeneyes are found on northern lakes and rivers that are surrounded by mature forests where tree cavities can be found for nesting. They prefer lakes with clear water and little emergent vegetation, although areas adjacent to bulrushes ( Scirpus ) are sometimes used for foraging. Preferred lakes are those with abundant invertebrate prey. Lakes that lack predatory fish, such as yellow perch ( Perca flavescens ), typically have the highest abundance of invertebrate prey.

During the winter, non-breeding season, common goldeneyes are found mainly in coastal marine and estuarine habitats and large, interior lakes and rivers. They prefer areas with shallow water and sandy, gravel, or rocky substrates. They are strong swimmers and can forage well in areas with strong current, but seem to prefer slow-flowing water. Common goldeneyes stop to refuel at large, interior lakes and rivers during migration towards coastal areas.

• Habitat Regions
• temperate temperate
• freshwater freshwater

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• coastal coastal
• brackish water brackish water

• Other Habitat Features
• estuarine estuarine

Physical Description

Common goldeneyes are medium-sized diving ducks. Males are slightly larger than females, from 45 to 51 cm in length (40 to 50 cm in females) and about 1000 grams (800 grams in females) weight. Males also have more brightly colored plumage for most of the year. Breeding males have a brilliant, greenish-black head marked with an oval, white patch at the base of the bill. Their sides, breast, belly, and secondary feathers are bright white and their back, wings, and tail are black. Female plumage is more muted, with rich brown heads, greyish backs, wings, and tails, and white sides, breasts, and bellies. Immature or eclipse males resemble females. Mature adults of both sexes have bright, deep, yellow irises, giving them the common name "goldeneye." Immature individuals have brownish irises. In flight their wings produce a whistling sound, which is characteristic.

The North American subspecies of common goldeneyes ( B. c. americana ) is larger overall and has a thicker bill than the Eurasian subspecies ( B. c. clangula ). Common goldeneyes can be confused with Barrow's goldeneyes ( Bucephala islandica ). However, adult male common goldeneyes have an oval white patch on the head (crescent shaped in Barrow's goldeneyes) and more white on the secondary feathers. Females are more easily confused, but female common goldeneyes have longer, sloping heads and bills and more white on the secondary feathers than female Barrow's goldeneyes. In western North America, female Barrow's goldeneyes have all yellow bills, common goldeneyes do not. This character does not work in other regions. Hatchlings of both species are also similar in appearance.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger
• sexes colored or patterned differently
• male more colorful

Reproduction

Common goldeneyes are monogamous. Pair bonds are formed in December and last until the male abandons the female at the beginning of incubation. It is unknown if pair bonds last over multiple years. Males use a complex set of courtship displays from December to March to establish and maintain the pair bond. Courtship displays occur in groups of several males and females, averaging 4.4 males and 1.2 females per group. There are variations on the displays. The most spectacular is the "head-throw-kick," in which a male repeatedly thrusts his head forward, then moves it back towards his rump and utters a call. He then flicks his head forward again while kicking the water with his feet.

• Mating System
• monogamous monogamous

Reproduction in common goldeneyes has been well-studied because they are relatively common in northern boreal areas and nest in boxes, making them easier to observe. Females lay from 4 to 12.3 greenish eggs in a clutch and lay a single clutch each season. Clutch size estimates are difficult to determine because of the frequency of intraspecific nest parasitism, which inflates clutch sizes. in one study average clutch size was 9.77, when parasitized nests were excluded, average clutch size was 7.13 eggs. Eggs are from 61.2 to 66.6 grams. Females lay 1 egg every other day.

Common goldeneyes nest in tree cavities, but will accept nest boxes and occasionally are found in rock cavities. Females find nest cavities and line them with a nest bowl constructed of other materials and downy feathers. Preferred nesting sites seem to be those used previously with success, rather than nesting sites closer to food resources for adults or young. Nests are generally within 1.3 km of water. Females who fail to breed successfully are more likely to change nest sites between years. Changing nest sites also seems to decrease reproductive success, producing smaller clutches. Females tend to nest in the general vicinity of their previous nest or natal nest. Younger females generally lay smaller clutches later in the season and have lower reproductive success than experienced breeders. After about 6 years old, clutch sizes begin to decline. Nest mortality is mainly due to predation. Clutches laid late in the year have higher mortality rates compared to early clutches.

Females incubate the eggs for 28 to 32 days. They leave the nest occasionally during the day to forage. Eggs hatch synchronously, within 12 hours of each other. Females first breed at over 2 years old, some researchers estimate breeding starts at about 3.2 years old on average and breeding continues annually for 3.9 years.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Young are precocial and leave the nest 24 to 36 hours after hatching. The mother attends the nest cavity entrance until all of the young jump to the ground. Females lead their brood away from the nest site to a brooding territory up to 10 km away. Only females defend the young and brood them at night and during cold weather. Females abandon their broods before they fledge, usually around 5 to 6 weeks old, but sometimes as early as 1 week after hatching.

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

Lifespan/Longevity

Adult females have a mean annual survival rate of from 58 to 77%, varying with study and region. Banding records in Canada suggest that males can live to 11 years and females to 12 years, although an unsexed individual was recorded living to 15 years. Hunting, predation, and diseases are noted as the leading causes of mortality in adults. Hatchlings are susceptible to cold, wet weather, which may result in mortality. Young suffer heavy mortality within the first few weeks of hatching.

Behavior

Common goldeneye populations migrate between their summer, breeding ranges and wintering grounds. They are often one of the last ducks to leave their summer grounds and will winter as far north as is possible in ice-free areas. Northward migrations towards breeding ranges begins in February in North America. Southward migration can begin as early as July, some populations begin migrating south as late as October. They generally migrate in small flocks of 4 to 40 individuals but will gather with other groups into large flocks at stopover areas. In summer females are generally solitary or found with their broods.

Common goldeneyes spend most of their time on the water. They only walk when moving broods from the nest to the water or overland to other lakes. They can fly up to 72 km per hour with 9 wingbeats per second. They fly low over the water in short-distance flights but fly at higher elevations when traveling over longer distances. Common goldeneyes are excellent swimmers and divers, they typically forage in small groups, diving synchronously to search for prey.

• Key Behaviors
• flies
• natatorial natatorial
• diurnal diurnal
• motile motile
• migratory migratory
• social social

Home Range

Home range sizes are not documented in common goldeneyes. They forage in small groups and are social except for the breeding season. Males defend small territories that include the nest during breeding season. They cease defending territories when females begin incubating eggs. Females also defend their nesting territory as well as a brooding territory once the eggs have hatched. Degree of territoriality may depend on local population densities. Densities have been estimated at from 0.5 to 3.5 pairs per km of shoreline in Minnesota. Female common goldeneyes show marked natal philopatry.

Communication and Perception

Common goldeneyes are mainly silent outside of the courtship and nest-finding period. Males make short, faint "peent" calls during courtship displays and grunting sounds after copulation. Females make "gack" sounds that are described as harsh croaks when looking for nest sites or when disturbed. Visual signals are used in courtship and aggression.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Common goldeneyes eat mainly aquatic insects during breeding season in northern, boreal lakes. In their winter ranges they rely on fish, crustaceans, and mollusks. They may also take some seeds and tubers. A study of 395 common goldeneyes throughout the year suggested that the majority of their diet is made up of crustaceans, insects, and mollusks (70% altogether), with the remainder made up of fish, eggs, and plant material. Diet is likely to vary regionally, but important crustaceans include crabs ( Hemigrapsus , Cancer , Pagurus , Cambarus , Astacus ), amphipods ( Ischyrocerus , Pseudalibrotus , Gammarellus , Hyalella ), shrimp, isopods, and barnacles. Important insect prey include caddisfly larvae ( Trichoptera ), water boatmen ( Corixidae ), dragonfly and damselfly nymphs ( Odonata ), mayfly nymphs ( Ephemeroptera ), and beetles ( Coleoptera ). Mollusk prey includes Mytilus , Lymnea , Macoma , Littorina , Nucula , Goniobasis , Nassarius , Lacuna , Bittium , and Mitrella . Fish prey may be locally important. For example, in British Columbia salmon and their eggs can make up a large portion of the diet. Other fish taken include sticklebacks ( Gasterosteidae ), sculpins ( Cottidae ), minnows ( Cyprinidae ), topminnows ( Poeciliidae ), and whitefishes ( Coregonus ). Plant matter taken includes freshwater pond weeds ( Potomogeton , Zostera , Ruppia , Najas , Zanichellia ) and spatterdock ( Nymphaea ).

Common goldeneyes typically hunt for prey in water less than 4 meters deep. They seem to prefer foraging in open water, although they may hunt along the edges of aquatic vegetation. They dive to catch prey and dives can be from 10 to 55 seconds long. Downy hatchlings mainly feed at the surface for their first few days but then begin short dives. Hatchlings forage in the same ways as adults, although they seem to be more selective about prey taken. They take greater proportions of dragonfly and damselfly nymphs ( Odonata ), caddisfly larvae ( Trichoptera ), and water boatmen ( Corixidae ). Foraging flocks often dive synchronously. Prey items are typically consumed underwater.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods
  • molluscivore molluscivore

• Animal Foods
• fish
• eggs
• insects
• mollusks
• aquatic crustaceans

• Plant Foods
• roots and tubers
• seeds, grains, and nuts

Predation

Most predation occurs on females and young in nests. North American predators of incubating females and hatchlings include black bears ( Ursus americanus ), American martens ( Martes americanus ), mink ( Neovison vison ), raccoons ( Procyon lotor ), hawks ( Accipitridae ), owls ( Strigiformes ), bald eagles ( Haliaeetus leucocephalus ), and golden eagles ( Aquila chrysaetos ). Hatchlings are also taken by northern flickers ( Colaptes auratus ), red squirrels ( Tamiasciurus hudsonicus ), and northern pike ( Esox lucius ). Hatchlings are cryptically colored and females have subdued plumage as well. Females defend their nests and broods with broken-wing displays.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Common goldeneyes compete directly with fish for prey and tend to be found on fish-free lakes more often than on lakes with fish. Removal of river perch ( Perca fluviatilis ) and roach ( Rutilus rutilus ) from a lake in Sweden resulted in increased use of that lake by common goldeneyes.

Like many other species of ducks , intraspecific nest parasitism is common in Bucephala clangula . Females whose nests are parasitized accept introduced eggs as their own but will abandon nests when too many introduced eggs are added to the nest in a short period of time. Common goldeneye females lay fewer of their own eggs when other eggs are introduced early in the egg-laying phase because they tend to brood only clutches of an optimal size. Levels of intraspecific parasitism vary substantially among populations and may be influenced by how limited nest cavities are in that area. Levels of parasitism range from 0 to 77.8% in British Columbia - seeming to vary mostly by local area and less year to year. Clutches with introduced eggs can be as large as 24, but most parasitized nests in British Columbia had less than 13 eggs in them.

Common goldeneyes are susceptible to botulism ( Clostridium botulinum ), avian cholera ( Pasteurella multocida ), and duck viral enteritis. Known parasites include several species of protozoans, flukes, and nematodes.

Economic Importance for Humans: Positive

Common goldeneyes are hunted throughout much of their range.

• Positive Impacts
• food food

Economic Importance for Humans: Negative

There are no known adverse effects of common goldeneyes on humans.

Conservation Status

Common goldeneye populations seem to be relatively stable despite threats to their aquatic habitats, such as acid rain, contamination, and habitat destruction. They are considered "least concern" by the IUCN because of their large range, large population size, and no documented population declines. They are protected as a migratory bird under the U.S. Migratory Bird Act. Population densities may be most affected by availability of nest cavities.

Other Comments

Common goldeneyes are sometimes called "whistlers" because of the whistling noise their wings make in flight.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Tanya Dewey (author), Animal Diversity Web.

References

Andersson, M., M. Eri. 1982. Nest Parasitism in Goldeneyes Bucephala clangula: Some Evolutionary Aspects. The American Naturalist , 120: 1-16.

Dow, H., S. Fredga. 1983. Breeding and natal dispersal of the goldeneye, Bucephala clangula. Journal of Animal Ecology , 52: 681-695.

Dow, H., S. Fredga. 1984. Factors Affecting Reproductive Output of the Goldeneye Duck Bucephala clangula. The Journal of Animal Ecology , 53: 679-692.

Eadie, J., M. Mallory, H. Lumsden. 1995. Common Goldeneye (Bucephala clangula). Pp. 1-20 in The Birds of North America Online , Vol. 170. Ithaca: The Cornell Lab of Ornithology. Accessed March 05, 2009 at http://bna.birds.cornell.edu.proxy.lib.umich.edu/bna/species/170 .

Eriksson, M. 1979. Aspects of the breeding biology of the goldeneye Bucephala clangula. Ecography , 2: 186-194.

Eriksson, M. 1979. Competition Between Freshwater Fish and Goldeneyes Bucephala clangula for Common Prey. Oecologia , 41: 99-107.