09. Chickadee Notes

Harlequin Duck in New Brunswick

Status

Harlequin DuckThe Harlequin Duck, Histrionicus histrionicus, is now a rare winter resident in New Brunswick, although one historical account suggests that it was a common wintering sea duck in the Bay of Fundy during the last century. As early as 1925 ornithologists noticed that the Harlequin population in this region had declined greatly, probably as a result of overhunting. Today the New Brunswick population consists of no more than 100 birds, confined principally to The Wolves, a series of rocky islands near Grand Manan. New Brunswick Harlequin are also occasionally observed during migration and winter in Passamaquody and Maces Bays and off Point Lepreau. Although the Harlequin Duck remains common on the Pacific coast it is estimated that the eastern North American population may be less than 1,000 birds.

...the New Brunswick population consists of no more than 100 birds.

In North America the Harlequin Duck is listed as a migratory gamebird under the Migratory Birds Convention Act of 1917 and since then has been a legal target species throughout its range. In the Atlantic region the open season on these birds has been closed since 1990. New Brunswick has protected the Harlequin Duck since 1987 with a ban on all waterfowl hunting on The Wolves. Since 1990 the eastern population has been listed as endangered by the Committee on the Status of Endangered Wildlife in Canada, a federal-provincial body which monitors the status of plants and animals in this country. Although the Harlequin Duck breeds in small numbers as far south as the Gaspe Peninsula, the bird has never been known to breed in the Maritimes.

Natural History

The male Harlequin Duck is a striking bird, readily identified by its distinct blue-gray plumage, chestnut flanks, and pronounced white patches on the head and body. The female Harlequin is dusky brown with white patches behind, below, and in front of each eye. The call of the Harlequin Duck is a mouse-like squeak, unlike that of any other sea duck, hence the nickname "sea mouse".

Outside North America the breeding range of the Harlequin Duck includes northern and eastern Asia, the islands of the Bering Sea, Greenland, and Iceland. On this continent the bird breeds from Alaska and the Yukon south through the western Mountains to central California and Wyoming and from Baffin Island and Labrador to the Gaspe. The species winters in coastal areas either near the breeding grounds or further south.

During the winter months Harlequin Ducks occupy exposed rocky shores and offshore ledges, usually where the swell is heavy and the water turbulent. Molluscs, barnacles, small crustaceans and echinoderms are principal items in the winter diet. The species is unique in that it is adapted to foraging over wave-pounded rocks and ledges where it pries its prey from vertical rock faces. Harlequin Ducks tend to fly close to the water in small, compact flocks. The species is not gregarious and coastal flocks are usually small, perhaps because the foraging habitat of wave-washed ledges and rocky shores are limited.

Eastern North American Harlequin move northward for the summer to nesting areas in the Gaspe, Newfoundland, and the coastal regions of Labrador, Quebec and southern Baffin Island. There are several tantalizing northern New Brunswick summer records of birds in suitable breeding habitat on the Benjamin and Nepisiquit Rivers, although nesting in this province has not been confirmed.

By waterfowl standards the species has a low reproductive rate...

Little is known of courtship behavior in this species but display activity has been observed on both wintering and summering grounds. Courtship displays consisting of head nodding are performed by both sexes and may include lateral bill shaking and bill dipping between nods. The male often launches a series of short rushes toward the female that conclude with his nibbling the side of her face.

Aquatic insect larvae are the principal food when on summer habitat. Nesting biology of the Harlequin Duck has been rarely studied. By waterfowl standards the species has a low reproductive rate, the result of small average clutch size (mean=5.7) and deferred sexual maturity of two to three years. Nests are built on the ground, often among thick shrub cover, and usually near swift rocky-bottomed rivers or streams. The four to eight eggs are laid one every two days and are light buff or cream coloured. Hatching occurs after a probable incubation period of 28 to 29 days. Within hours of hatching the nestlings follow their mother to the water and in about 40 days the young are ready to fly.

About the time the females start incubating, males desert their mates and congregate to undergo their post-nuptial moult. The flightless period of the moult proceeds away from the summer nesting grounds, perhaps at sea. Some females have been observed moulting in their breeding areas, but others leave their broods and fly elsewhere to undergo their flightless period. Perhaps this is why brood mergers are common, with unsuccessful breeding age females sometimes joining such groups.

Helping Out

The ban on the hunting of waterfowl on the principal New Brunswick wintering ground off The Wolves offers considerable protection for this bird. Additionally, the federally regulated hunting season on Harlequins in the Atlantic region is now closed. Although it is difficult to mistake a male Harlequin for any other waterfowl species, females and immatures are relatively drab and can be confused with other sea ducks such as scoters. Hunters should ensure they are familiar with the plumages of all ducks they might encounter and should always identify their target before shooting. Marine pollution, particularly oil, could affect Harlequins directly, or indirectly, by reducing their prey populations. Anyone working on boats at sea should take the necessary steps to prevent oil or chemical spills, particularly adjacent to rocky shores where Harlequin winter. We can all play a role in preventing further degradation of the marine environment the Harlequin depends on by keeping litter off the shoreline and insisting that the problem of marine pollution become a matter for the urgent attention of legislators.

Further Reading

Bellrose, F.C. 1978. Ducks, geese and swans of North America. The Stackpole Company, Harrisburg, Pennsylvania. 540 pp.

Godfrey, W.E. 1986. The birds of Canada. National Museums of Canada, Ottawa. 596 pp.

Goudie, I.R. 1990. Status report on the Harlequin Duck (eastern population) Histrionicus histrionicus. Committee on the Status of Endangered Wildlife in Canada, Ottawa. 61 pp.

Johnsgard, P.A. 1978. Ducks, geese and swans of the world. University of Nebraska Press, Lincoln, Nebraska. 404 pp.

Vickery, P.D. 1988. Distribution and population status of Harlequin Ducks, Histrionicus histrionicus, wintering in eastern North America. Wilson Bulletin 100:119-176.