Common Goldeneye (Bucephala clangula)
By Wanda Gorsuch

Common Names: Whistler

Common goldeneyes get their common name ‘whistler’ from the whistle of their wings that is often heard before they are even seen.  Flying fast, in small flocks, no other duck flies as consistently in tight formation.

Identification

Common goldeneyes are a chunky medium sized diving duck.  Males are noticeably larger being about 45-51cm in length and weighing an average of 1000g while hens are 40-50cm in length and weigh in at an average of 800g.

Males have a beautiful iridescent greenish-black head and a distinctive oval white patch at the base of the bill.  Sides, breast, belly and secondaries are a bright white.  Back, wings and tail are a contrasting black.  Adult males resemble male Barrow’s goldeneye, but have an oval versus crescent shaped head patch, more white on head and secondaries and a more peaked head with a longer, sloped bill.

In contrast, hens have a chocolate brown head, with slate gray back wings and tail.  Flank, belly and breast are white.  Hens are easily confused with Barrow’s goldeneye hens.  Common goldeneye hens have a longer, sloped forehead and bill along with more white secondaries. 

Distribution

A cold hardy duck, during the breeding season, common goldeneyes are found in the boreal forest tree line from the eastern provinces west to Alaska and south in the Acadian and Great Lakes forest region, aspen parklands, montaine forest and wherever trees are large enough to provide nesting cavities.  Main breeding areas are from Labrador west through central Ontario to British Columbia and north to Great Slave Lake.

During winter, the highest concentrations of common goldeneyes can be found from coastal northern New England south to Chesapeake Bay and the coasts of south-west Alaska and British Columbia.  Overall winter range includes southern Canada down through the USA (both east and west) to just in to Mexico.  Some birds spend their winter in Bermuda.

Habitat

During breeding season, common goldeneyes favor wetlands, lakes and rivers bordered by forests with trees large enough to provide suitable tree cavities for nesting.  In some northern areas, common goldeneyes have been known to use rock cavities as well.  Ready availability of invertebrate prey may be a factor in influencing habitat choice.

Common goldeneyes favor marine areas in the winter.  These include shallow coastal bays, estuaries and harbors on the Pacific and Atlantic coasts.  In the interior, they are found on larger lakes and rivers as far north as open water is available.

Food

What common goldeneyes eat vary by season and if they are on fresh or salt water.  During breeding season, they mostly prefer insects such as dragonfly and damselfly nymphs and caddisfly larvae.  In contrast, fish, crustaceans and mollusks are an important part of their winter diet.

Reproduction

Currently, researchers are uncertain when pair bonds are formed.  It is thought that it happens in winter to early spring.  Nesting starts around April and can extend in to June. 

Hens generally use the same nest site they used the previous year.  First time layers look for prospective nest cavities the summer before they start nesting.  Cavity nesters, common goldeneyes will also readily use artificial nest boxes.  Nests can be right beside water, or up to 1.3km away.  Cavities can be formed from pileated woodpeckers, broken tree limbs and hollow tops of standing trees.  Cavities are usually 1.3m to 13m above the ground.

The nest bowl is created from material already in the cavity.  5 – 15 eggs are laid, one every other day, usually in the morning or late afternoon.  It is not unusual for a hen to lay her eggs in another hens nest.  This is called egg dumping or nest parasitism. 

Incubation length increases as more eggs are laid.  Only hens incubate.  Eggs are incubated for 28 – 32 days.  Eggs generally hatch within 12 hours of each other, often over night or in the early morning.  Ducklings stay in the nest for 24 to 36 hours after hatching.  When it is time to go, the hen flies repeatedly to the cavity, than sits below the nest on the ground, calling.  Ducklings jump from the nest and are led to water, which can be up to several kilometers away.  Ducklings are able to feed themselves from the time of hatching.

Conservation and Management

Population data suggests that populations are stable and there is no significant trend in population size.  However, there are concerns about habitat loss, for example, in the Great Lakes –St. Lawrence lowlands and the boreal forest.

Sources of Information

Bellrose, F.C.  1976.  Ducks, geese and swans of North America, 2^nd edition. Stackpole Books, Pennsylvania.

Eadie, J.M., M.L. Mallory, and H.G. Lumsden.  1995.  Common Goldeneye (Bucephala clangula). In The Birds of North America, No. 170 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists’ Union.

Johnsgard, P.A.  1978.  Ducks, geese, and swans of the world. University of Nebraska Press, Nebraska.