[order] Anseriformes | [family] Anatidae | [latin] Bucephala islandica | [UK] Barrows Goldeneye | [FR] Garrot d'Islande | [DE] Spatelente | [ES] Porrón Islándico | [IT] Quattrocchi islandico | [NL] Ijslandse Brilduiker

Ijslandse Brilduiker determination

copyright: youtube

Barrow’s goldeneyes are chunky mid-sized sea ducks with short necks, a relatively large rounded head, and a short gray-black bill. Males are markedly larger than females; males are about 48 cm and females about 43 cm. Spring weights for males average 1278 g and 818 g for females. Male Barrow’s goldeneyes in breeding plumage have an iridescent purplish-black head with a crescent-shaped white patch between bill and eye, white sides, belly, and breast, and black back, wings and tail. They also sport a series of seven white chevrons along their sides. Females have a dark chocolate-brown head, slate-gray back, wings, and tail, and white flanks, belly and chest. Immatures and eclipse (molting) plumage males resemble females. Both males and females have bright amber irises, hence “goldeneye”. In flight, their wingbeat is rapid and they make a distinctive whistling sound - they are also called “whistlers”. Both males and females have a white patch on their secondary (inner) wing feathers and a white bar above that on the inner upper wing that is more distinct on adult males than on females or immatures. Barrow’s goldeneyes can be most easily distinguished from common goldeneyes by the male’s crescent-shaped white patch on its bill, the steeper angle between bill and forehead, and shape of head - Barrow’s have steeper foreheads than common goldeneye, which have sloping foreheads more like canvasbacks.

Barrow’s goldeneyes breed primarily on alkaline to freshwater lakes and to a lesser extent on subalpine lakes, beaver ponds, and small sloughs in western mountain and intermountain areas. In Quebec, they prefer small fishless lakes that are found above 500 m elevation.

The breeding range of Barrow’s goldeneyes is generally restricted to areas west of the Rocky Mountains from Montana to Alaska, and to a core brecding area in the east on the high plateau along the north shore of the St. Lawrence estuary and gulf. There is no evidence of exchange between the eastern and western populations. The core of the western Barrow’s breeding population is in interior areas of British Columbia. Their primary breeding range extends northward through southern Yukon into southcentral Alaska. Elsewhere within their western range, they are found locally or in lower densities. Wintering areas in the west are coastal and extend from Kodiak archipelago, Alaska, south into Washington, with more localized occurrences south to San Francisco Bay and open waters of northwestern states. Most eastern Barrow’s winter in the St. Lawrence estuary with smaller wintering populations along the Gaspe Peninsula, the Maritime provinces, and Maine.
Bucephala islandica breeds in Europe only in Iceland, which accounts for a tiny proportion of its global breeding range. Its European breeding population is very small (as few as 500 pairs), but was broadly stable between 1970-1990, and—despite substantial fluctuations—remained broadly stable overall during 1990-2000. Nevertheless, the entire European breeding population is confined to just a handful of locations in north-eastern Iceland, with the vast majority (85-90%) concentrated at just one site (Lake Mývatn and the River Laxá). Consequently, it is evaluated as Vulnerable.

These diving birds forage underwater. They eat aquatic insects, crustaceans and pond vegetation.

This species has a large range, with an estimated global Extent of Occurrence of 1,000,000-10,000,000 km². It has a large global population estimated to be 180,000-210,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]

Many female Barrow's Goldeneyes don't start breeding until the age of three years, but younger females may prospect for future nest sites. Females typically return to the areas where they hatched, and once they begin to breed, often return to the same nesting site year after year. Pairs form in late winter or early spring. Nests are typically located in cavities in large trees or nest boxes, although Barrow's Goldeneyes have been known to nest in rock crevices, abandoned buildings, burrows, or in bushes on the ground when trees aren't available. The nest itself is a depression in existing material (wood chips, leaves, or material from a previous nest), lined with down. The female typically lays 6 to 12 eggs and incubates them for 29 to 31 days. After incubation has begun, the pair bond dissolves and the male begins his molt migration. The long-term pair bond is re-established in the fall. The young leave the nest one to two days after hatching, and the female leads them to an area with abundant food where they feed themselves. Broods sometimes join other broods and create large crèches. This most often occurs if a brood has been abandoned early by the female, or if broods are mixed up during territorial disputes between females. Females abandon the young before they can fly, usually at 5 to 6 weeks of age, but occasionally earlier. The young fledge at 8 to 9 weeks of age.

Not truly migratory; some populations (e.g. Iceland, southern Rocky Mts) mostly sedentary, whereas others undertake longer trips to winter along Pacific coast of Alaska and Canada and Atlantic coast of NE North America. A few record W Europe, possibly better attributable to escapes.