Barrows Goldeneye (Bucephala islandica)

Barrows Goldeneye

[order] ANSERIFORMES | [family] Anatidae | [latin] Bucephala islandica | [authority] Gmelin, 1789 | [UK] Barrows Goldeneye | [FR] Garrot de Islande | [DE] Spatelente | [ES] Porron Islandico | [NL] IJslandse Brilduiker

Subspecies

Monotypic species

Genus

Goldeneye are small tree-hole nesting northern hemisphere seaducks belonging to the genus Bucephala. Their plumage is black and white, and they eat fish, crustaceans and other marine life.

The Bufflehead was formerly separated in its own genus Charitonetta, while the goldeneyes proper were mistakenly placed in Clangula, the genus of the Long-tailed Duck which at that time was placed in Harelda.

Physical charateristics

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.

Listen to the sound of Barrows Goldeneye

[audio:https://planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/Barrows Goldeneye.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: cm wingspan max.: cm
size min.: 43 cm size max.: 48 cm
incubation min.: 29 days incubation max.: 31 days
fledging min.: 0 days fledging max.: 31 days
broods: 1   eggs min.: 6  
      eggs max.: 12  

Range

North America : nw, Northeast, also Iceland

Habitat

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.

Reproduction

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 creches. 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.

Feeding habits

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

Video Barrows Goldeneye

httpv://www.youtube.com/watch?v=3eTTocoUiu4

copyright: youtube


Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
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 Myvatn and the River Laxa). Consequently, it is evaluated as Vulnerable.
Barrows Goldeneye status Least Concern

Migration

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.

Distribution map

Barrows Goldeneye distribution range map

Literature

Title A Management Plan for Barrow’s Goldeneye (Bucephala islandica; Eastern population)
Author(s): Schmelzer, I.
Abstract: The world distribution of Barrow’s Goldeneye (Buce..[more]..
Source: Wildlife Division, Department of Environment and Conservation. Corner Brook, NL.

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Title Moult characteristics and habitat selection of postbreeding male Barrow’s Goldeneye (Bucephala islandica) in northern Yukon
Author(s): van de Wetering, D. E
Abstract: Moult characteristics and habitat selection of pos..[more]..
Source: M.Sc. thesis, Simon Fraser Univ., Burnaby, BC, Canada.

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Title Further Evidence of Long-term Pair Bonds in Ducks of the Genus Bucephala
Author(s): GILLES GAUTHIER
Abstract: In holarctic ducks, pair formation occurs during t..[more]..
Source: Auk, Vol. 104

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Title BODY WEIGHT AND FEATHER GROWTH OF MALE BARROW’S GOLDENEYE DURING WING MOLT
Author(s): DEBBIE VAN DE WETERING and FRED COOKE
Abstract: We studied the timing, duration, and rate of wing ..[more]..
Source: The Condor 102:228-231

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Title Processes underlying parental care decisions and creching behaviour: clarification of hypotheses
Author(s): Hannu Poysa and Markku Milonoff
Abstract: Processes underlying parental care decisions and c..[more]..
Source: Ann. Zool. Fennici 36: 125-128 Fennici 36: 125-128

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Title TRACING NUTRIENT ALLOCATION TO REPRODUCTION IN
BARROW’S GOLDENEYE
Author(s): KEITH A. HOBSON et al.
Abstract: Naturally occurring stable isotopes in foodwebs ca..[more]..
Source: JOURNAL OF WILDLIFE MANAGEMENT 69(3):1221-1228; 2005

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