Goldeneyes

Full Species Account

 

Two species of goldeneyes (a type of sea duck) are winter visitors to Peaks Island: Barrow’s Goldeneye (Bucephala islandica) and Common Goldeneye (Bucephala clangula) (1, 2). A striking feature is their bright golden-yellow eye.

 

Several Common Goldeneyes were observed throughout the winter in Wharf Cove and along the Backshore – sometimes in pairs or singly. The less common Barrow’s Goldeneye was repeatedly observed in Woodcutter’s Cove (end of Great Pond Road) – also confirmed by members of Audubon’s Christmas Count.

 

Goldeneyes pursue their prey by diving, or if in shallow water they may dabble.  Both species feed on invertebrates in the winter and select insects, larvae, and plant material on their breeding grounds. The Common Goldeneye may also feed on small fish. (1)

 

Male goldeneyes are black and white: their backs are mostly black and their bellies are white. The Barrow’s Goldeneye’s back plumage has less white within the black background, i.e., it appears at a distance blacker than the Common Goldeneye. The Common Goldeneye’s back shows more white interspersed with delicate wisps of black; at a distance it appears less black on its back. In flight the Common Goldeneye also has more white on its wings – the secondary flight and covert feathers. The Barrow’s Goldeneye’s head has a glossy-purplish sheen while the Common Goldeneye head takes on a glossy-greenish shine. These differences are subtle at a distance, however the white spot behind the bill is a better indicator of the two species: on the Barrow’s Goldeneye’s it is crescent shaped while the Common Goldeneye has a round spot. (1, 3, 4) (see above)

 

The differences between the females are even subtler. The Barrow’s Goldeneye’s chestnut brown head is distinctly rounded and it has a vertical forehead. The Common Goldeneye head is more triangular. Both species have a greyish body plumage and in flight display striking white secondary flight feathers against dark wings. The female Barrow’s Goldeneye has one band of white covert feathers over the flight feathers whereas the Common Goldeneye has two rows of these white feathers (see above). In flight we might see these small differences as simply more white on the wingback on the Common Goldeneye (as does the male) as compared to the Barrow’s Goldeneye. (1, 3, 4)

 

As similar as the two species are in appearance, they are dissimilar in their geographic ranges, their migration distances, and their courtship displays.  The Barrow’s Goldeneye has a small breeding range; they migrate very short distances; and their courtship is a little rough. The Common Goldeneye, on the other hand, has large expansive breeding ranges, migrates great distances, and has more peaceful, yet elaborate, courtships.  

 

The Barrow’s Goldeneye distribution is restricted to North America. Its westerly range includes Alaska, Washington, and the Canadian Rockies - they migrate short distances from the coastal areas to inland waters to breed. The Barrow’s Goldeneye’s easterly range is sparse. The non-breeding populations are found along the Gulf of St. Lawrence and coastal shores as far as south as Long Island. Migration distances are short to breeding grouns; it flies from the New England coast and St. Lawrence to Labrador. The populations on Greenland (which may be a relic) and Iceland are very small and their movements within each island are minimal. (3)   

 

The Common Goldeneye originated in North America (NA) - expanding from Alaska to the Canada Maritimes. After this expansion this highly successful goldeneye has extended its distribution across Eurasia. In the winter in NA the Common Goldeneye is found along the coast of Alaska south through California; along the Mississippi River Valley; and the East Coast from Nova Scotia to Georgia. Migration distances from coastal and inland areas to breeding grounds across Canada are more distant than the Barrow’s Goldeneye. (3)

 

Pairs may form in the winter, or later when they are closer to breeding grounds. These ‘sweet’ appearing sea ducks, in particular the male Barrow’s Goldeneye, can be aggressive during courtship. This goldeneye will place its neck on the water surface, dive below the surface, and make a deliberate attack from underwater upon another male duck. The two males will rise together, breast to breast, and beat each other with their wings. If another unrelated water bird is in close proximity, they may find themselves in the middle of this beating. And, females too can be a little over zealous in their competition for the favored male. The male Common Goldeneye, however, is not aggressive, but instead he uses an acrobatic “kick-display” to impress his fancy. The male places his head and neck forward, throws this head backwards (ouch), rests it on his back, points his bill upward, and then - kicks his legs backwards (3). Try it. Very early one morning on Woodcutter’s Cove I observed very strange Common Goldeneye behaviors – was it only my caffeine-free imaginations or was it --- The “kick-display”? 

 

In April to May the goldeneyes migrate to fresh water lakes, ponds, or rivers.  The Common Goldeneye prefers coniferous forests with natural holes for nesting.  The Barrow’s Goldeneye also prefers tree holes for its down covered nest, but will settle for a crevice or thick vegetation. The Common Goldeneye that has an expansive breeding range, globally, does not nest on treeless Iceland or Greenland where there are no nest holes. Even though the Barrow’s Goldeneye has such a limited breeding range it nests in treeless Greenland and Iceland – because it can tolerate other nest types and perhaps takes advantage of no competition for nest sites with the Common Goldeneye.  Both species have from 8-11 eggs, incubation is from 28-30 days, and the young chicks have dark brown down on their backs with whitish down on their bellies.  They fledge in 57-66 days and are sexually mature at two years of age. (1, 3)  

 

References

1. del Hoyo, J., Elliott, A., and Sargatal, J. eds. (1992). Handbook of the Birds of the World. Vol. 1. Lynx Edicions, Barcelona (pages: 620, 623).

 

2. del Hoyo, J., and N.J. Collar. 2104. Handbook of the Birds of the World and Birdlife International Illustrated Checklist of Birds of the World. Lynx Edicions, Barcelona (page: 132-133).

 

3. Gooders, J. and T. Boyer. 1986. Ducks of North America and the Northern Hemisphere. Dragon’s World Ltd (pages:141-148).

 

4. Sibley, D.A.  (2000). National Audubon Society: The Sibley Guide to Birds.  Alfred A. Knopf, Inc. NY (page: 100).

 

Written by: Patty Wainright

Reviewed by: Sam Wainright and Michelle Brown