Barnacle Goose

The barnacle goose (Branta leucopsis, known as Nerlernarnaq in Greenlandic) breeds in the Arctic region only in East Greenland, Svalbard (Spitsbergen), and Novaya Zemlya, Russia. The barnacle goose is not divided into subspecies, but three "flyway" populations have been recognized that correspond to the three breeding areas. In the early 1970s, the Russian population started to breed in the temperate Baltic Sea region.

The barnacle goose is a rather small goose 60-70 cm (24-28 in) long and weighing of 1-2 kg. The face is yellowish, with the rest of the head, neck and breast, as well as bill and feet, in black. The underparts are white and the back and upper wings are bluish-gray. Young birds are similar, but more drab and with a white face.

The nesting habitats of the barnacle goose are cliff ledges on coastal cliffs and canyons, rocky outcrops, and small offshore islands. the most important breeding sites are on Svalbard and in Russia coastal islands, some holding 1000 nests. In Greenland the colony size varies from ten to 150 pairs.

The barnacle goose migrates to wintering grounds in Ireland and northwest Scotland (Greenland population), the Solway Firth in southwest Scotland (Svalbard population), and the Netherlands (Russian population). The winter habitats are mainly salt marshes on offshore islands, in fjords or in the Wadden Sea, but intensively managed grasslands are also important feeding areas.

All three flyway populations are increasing in numbers, and according to the 1994-1997 population estimates the total wintering population numbers around 330,000 birds. Of these the Russian population is by far the largest with about 270,000 birds, while the Greenland population holds 40,000 birds and the Svalbard population 23,000 birds.

The Greenland and Svalbard populations both have long migration routes across sea, and they leave their wintering grounds during mid-April and early May to stop over at sites in northern Iceland and the Helgeland archipelago off the Norwegian coast, respectively. During a two- to three-week period, they build up energy stores before continuing their migration to the breeding areas. In mild winters, the Russian population leaves the Netherlands wintering grounds in January and moves slowly northeast. The staging areas in the Baltic Sea region are reached in early April, and the geese proceed to the breeding grounds around mid-May. All three populations have migration routes of 3000-4000 km (2000-2500 mi).

The geese start breeding in late May to early June. The nest is a shallow depression lined with down, moss, and grass. Here the female incubates a clutch of four to five eggs for 23-25 days. The goose leaves the nest for an average of 3% of her time on short feeding trips. These feeding trips are not sufficient to maintain her body mass and about 40% of her body mass may be lost by the end of incubation. Females that are able to find high-quality food during their short absence from the nest breed more successfully. During incubation, the males defend the nest against predators such as the glaucous gull Larus hyperboreus, the rough-legged buzzard Buteo lagopus, and the Arctic fox Alopex lagopus. When the goslings hatch, the male has lost about 20% of his weight, but this weight loss continues because he must stay vigilant in order to protect the goslings from predators. Goslings that jump from cliff ledges suffer losses of about 50% when they disappear in the scree or are taken by Arctic foxes, gulls, and falcons. The breeding success of the Russian population varies considerably, with anything from a few percent to 50% young birds surviving to reach the wintering grounds. This variation is linked to the production of lemmings (Lemmus sibiricus and Discrostonyx torquatus), which in turn controls the Arctic fox population. When the fox population peaks, the lemming populations have often collapsed, which forces the foxes to predate on goslings. Wetlands in the high Arctic tundra are selected for the rearing of young. These wetlands include sedge and moss marshes, with cotton grasses Eriophorum in drier areas. The goslings are able to fly when about six weeks old.

Like other goose species, the barnacle geese have only one body molt every year, and the most conspicuous is the wing molt. The duration of the wing molt is three to four weeks, and the development of the flying feathers is more rapid than in many duck species, indicating an adaptation to the short Arctic summer in the Arctic-breeding goose species. Immature geese and failed breeding birds molt in July, while breeding birds molt about two weeks later. No molt migration out of the breeding range has been observed in the Svalbard and Russian populations. A southward molt migration, unusual in Arctic geese, takes place in the Greenland population, where 5000-6000 geese congregate in the southernmost breeding range. Here, the barnacle goose is competing with the pinkfooted goose Anser brachyrhynchus for the limited food resources. The molting sites contain refuge lakes or rivers, and abundant food resources. During molt, up to one-third of the total body protein content is lost. Despite this loss over a relatively short period, geese are able to meet their energy and protein demands through moderate feeding, and do not have to deplete their energy and nutrient reserves. During this period, proteins are degraded from the breast muscles and built into leg muscles. These changes are ascribed to disuse-use of the muscle groups.

The autumn migration starts in late August and early September and wintering grounds are reached in October and November. All three populations have stopover sites where they stay for about three weeks, building up energy reserves and waiting for favorable tailwinds: the Greenland population stopover in southeast Iceland, the Svalbard population at Bj0rn0ya, 250 km (150 mi) south of mainland Svalbard, and the Russian population in the Baltic Sea region.

Since 1950-1980, the barnacle goose has been protected from hunting throughout its range, except for Iceland and Greenland, where about 4000 geese are legally shot annually. Local people used to gather eggs and down. In Greenlandic myths, geese have the ability to return sight to blinded people by squirting people's eyes with their feces.

Christian M. Glahder

See also Brent Geese

Further Reading

Batt, B.D.J., A.D. Afton, M.G. Anderson, C.D. Ankney, D.H. Johnson, J.A. Kadlec & G.L. Krapu (editors), Ecology and Management of Breeding Waterfowl, Minnesota: University of Minnesota Press, 1992 Cramp, Stanley & K.E.L. Simmons (editors), Handbook of Birds of Europe, the Middle East, and North Africa: The Birds of the Western Palearctic, Volume 1, Oxford: Oxford University Press, 1977 del Hoyo, Josep, Andrew Elliott & Jordi Sargatal (editors), Handbook of the Birds of the World, volume 1, Barcelona: Lynx Edicions, 1992 Madsen, Jesper, Gill Craknell & Tony Fox (editors), Goose Populations of the Western Palearctic. A Review of Status and Distribution, Wetlands International Publ. No. 48, The Netherlands, Wageningen: Wetlands International; Denmark, Rönde: National Environmental Research Institute, 1999

Owen, Myrfyn, Wild Geese of the World. Their Life History and

Ecology, London: B.T. Batsford Ltd., 1980 Rose, P.M. & D.A. Scott (compilers), Waterfowl Population Estimates (2nd edition), Wetlands International Publ. No. 44, The Netherlands, Wageningen: Wetlands International, 1997 Salomonsen, Finn, "The moult migration." Wildfowl, 19 (1968): 5-24

-, Grönlands Fugle. The Birds of Greenland, K0benhavn:

Munksgaard, 1950

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