[order] Anseriformes | [family] Anatidae | [latin] Branta bernicla | [UK] Brent Goose | [FR] Bernache cravant | [DE] Ringelgans | [ES] Barnacla de Cara Negra | [IT] Oca colombaccio | [NL] Rotgans

Rotgans determination

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The Brant is similar in appearance to the Canada Goose, but smaller and darker. The adult has a gray belly and breast, white rump, and black neck and head with a thin white necklace and no chin-strap.
Fast fliers with swept-back wings, Brant are usually found in a flock. They forage while wading, dabbling in shallow water, or while walking on mudflats or the shore. They display strong site-fidelity to both their wintering and nesting areas.

Brant are almost exclusively coastal in their range and are found in shallow bays and saltwater marshes. They nest in the wet, coastal tundra of the high Arctic. Their winter habitat is closely tied to the occurrence of sea grasses and marine algae.

Branta bernicla is a rare breeder in the European Arctic, but winters mainly in coastal areas of western Europe, which accounts for less than half of its global wintering range. Its European wintering population is large (>240,000 individuals), and increased between 1970-1990. Although a few populations increased or were broadly stable during 1990-2000, key wintering populations (of the subspecies B. b. bernicla) in the United Kingdom, France and the Netherlands declined, and the species underwent a large decline (>30%) overall.
This goose is breeding on the arctic coasts of Eurasia and North America, mainly on small islets protected from polar foxes (Alopex lagopus). It winters along the temperate Atlantic and Pacific coasts. The birds visiting the European Union belong to three different populations (Scott & Rose). The first population, estimated at 20000 individuals, comprises the white-bellied birds of the race hrota, breeding in Greenland and northern Canada and wintering in Ireland. The second population, estimated at 5000 individuals, comprises the birds of the race hrota breeding on Svalbard and wintering in Denmark and north-eastern England. The third population, estimated at 300000 individuals, comprises the dark-bellied birds of the nominate race, breeding along the Russian coasts and wintering in Denmark, Germany, the Netherlands, south-western England and France. All three populations have undergone important fluctuations. The nominate race has experienced a 90% decline during the 1930's following a disease of its foodplant, Zostera marina. It has started to recover since the 1950's, and the increase is still in progress. The populations of Canada and Greenland have increased since the 1960's and seem currently to be stable. The population of Svalbard dropped from about 40000-50000 to a mere 2000 at the end of the 1960's, not only because of the disease of Zostera but also because of non sustainable hunting. Since the 1970's it has recovered

Historically, Brant fed almost exclusively on eelgrass, which is still strongly preferred when available. Now they also forage on grasslands and have been able to diversify their diet in the absence of eelgrass, although their range is still closely tied to eelgrass. Brant also eat some aquatic invertebrates.

This species has a large range, with an estimated global Extent of Occurrence of 100,000-1,000,000 kmē. It has a large global population estimated to be 570,000 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]

Long-term pair bonds usually form on the wintering grounds. Nesting occurs in loose colonies, on small islands in tundra ponds. The breeding range of the Brant is typically within five miles of the coast. The nest is a shallow bowl of grass and other vegetation, lined with down. The female incubates 3 to 5 eggs for 22 to 24 days. The young leave the nest within a day of hatching, and both parents continue to tend them and lead them to sources of food. During the long days of the high-Arctic summer, the young feed at all hours, and grow quickly. They fledge at 40 to 50 days, but stay with the parents through the first migration.

Single wholly migratory population. Depart Russian tundras mid-August to 1st week September. Main route west along arctic coasts to White Sea, then overland to Gulfs of Finland and Bothnia. Passage through Baltic mid-September to early October; first arrivals Denmark late September but bulk October. Some stay Denmark and western Germany through November before moving on in colder weather; others go straight to winter quarters in Netherlands, south-east England, and west France, where peak numbers December-February. Return passage begins early March; most leave England and France by mid-April. Spring gatherings in Netherlands, Denmark and western Germany until main departures in mid-May; only stragglers after mid-June.