(originally published to Helium writing site, now gone)
Barrow’s goldeneye, or Bucephala islandica, is found mainly in lake and wooded pond areas in north-eastern America but also in Canada and Iceland. Its name comes from the Icelandic word for “bullhead”. An adult is about 13 inches long with a wingspan of 31 inches. It is a waterfowl of the diving duck variety.
Adults have a large, oval shaped head with steep forehead and a fairly short bill. The male’s head is metallic black and purple which becomes an iridescent green in the right light and angle. It has a defining yellow or golden eye and a white patch on its cheek. The bird has a black bill and back, while its wings are also black but with white patches or stripes. Its chest and underbelly are white. In contrast, the female’s head is dark brown and its body is gray. Her dark gray bill has a pinkish yellow tinge. The feathers of Barrow’s goldeneye change color with the seasons. The colors described above are those observed in the warmer months. Both males and females have a much duller coloring in the cooler months. Immature birds have similar coloring to the adult females except for a darker bill.
Barrow’s goldeneye has a single mate and breeds from about two years of age. Pairing starts in the late winter. They build nests in tree cavities, although sometimes they will make a burrow in the ground, in a hollow stump, or in a rock crevice. Nests are made of small twigs and moss, with a lining of down. The birds are happy to use old nests. The female will lay about six eggs which are pale blue in color. Incubation time is around one month, before the young are hatched. A pair will usually have only one brood a year. Occasionally, they may have a second brood, especially if the first chicks die for whatever reason very soon after hatching.
The bird’s habit of using a tree hole as a nest means it is often described as an arboreal duck, “arboreal” meaning “relating to trees”. The main reason it nests in trees is to protect its young from predators. Sometimes the nest will be one or two miles from water. Within hours of hatching, the female somehow gets the ducklings to jump from the tree. Sometimes a nest will be 30 or more feet above the ground, so injury and death is a great risk. She will then lead her chicks to the nearest lake or creek.
Its main source of food is aquatic invertebrates such as mollusks. It will also eat fish eggs, fish, shellfish, insects, frogs, seeds and certain plants. Barrow’s goldeneye is an accomplished diver, frequently diving to the bottom of shallow water to obtain its food. When it flies, its wings make a kind of whistling sound.
Until 1998, little was know of the breeding habits of the Barrow’s goldeneye or where they went to breed. Indeed, no one had found any evidence of nesting anywhere in eastern North America. A study in Quebec in 1998 used satellite transmitter implants to track the movements of seven males. Flocks migrated inland to an area of small lakes in the highlands on the north side of St Lawrence River. Mating occurred in the area, the first recorded breeding of Barrow’s goldeneye in North America. About 2,000 to 4,000 birds spend winter in Quebec along the Gulf of St Lawrence and the St Lawrence River and its estuary. The largest flocks can be found in places such as La Malbaie-Pointe-au-Pic, Baie-Comeau, Baie-des-Rochers, Peninsule de Gaspe and the Ile d’Anticosti.
Numbers of Barrow’s goldeneye may be declining. Surveys conducted in the St. Lawrence estuary indicated a fall of about 35 per cent between the early 1980s and late 1990s. The population appears vulnerable to logging during the breeding season due to their dependence on trees for nesting. Luckily, loggers prefer trees without cavities, although the bird uses large trees and these are rare in this cold climate. A program of artificial nesting boxes has helped relieve the situation. These birdhouses have a floor of eight inches square, a ceiling 15 inches high, and an entrance of three inches. They are placed 10 or more feet above the ground.
Other threats to the Barrow’s goldeneye include potential oil spills and hunting. An oil spill in the St Lawrence estuary could result in the death of a significant number of these waterfowl. Also, much of their winter habitat could be polluted, forcing them to find other locations, which may result in a further decline in numbers. The bird is vulnerable to the fall hunting season. Shooting of both the Common goldeneye and the rarer Barrow’s goldeneye is now forbidden from mid October in areas frequented by the latter as it can be hard to tell the difference between the two birds. The Committee on the Status of Endangered Wildlife in Canada gave goldeneye a “Special concern status” in 2011.