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LC
Brent Goose Branta bernicla

Justification
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 is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds 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.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: #http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls#.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

Taxonomic note
Branta bernicla (Sibley and Monroe 1990, 1993) was putatively split into B. bernicla, B. hrota and B. nigricans by Shields (1990) but this treatment is not followed by the BirdLife Taxonomic Working Group.

Population justification
The global population is estimated to number > c.560,000 individuals (Wetlands International 2006), while national population sizes have been estimated at <c.1,000 wintering individuals in Korea and c.50-1,000 individuals on migration and c.50-1,000 wintering individuals in Japan (Brazil 2009).

Trend justification
The overall population trend is uncertain, as some populations are decreasing, while others are stable, have unknown trends or are increasing (Wetlands International 2006). This species has undergone a small or statistically insignificant increase over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007).

Ecology
Behaviour This species is fully migratory, the main routes of migration being along Arctic coastlines (Snow and Perrins 1998). It arrives on the breeding grounds in early-June (Madge and Burn 1988, Scott and Rose 1996) where it may breed in small, loose colonies (Madge and Burn 1988, del Hoyo et al. 1992, Snow and Perrins 1998) or dispersed in single pairs (Snow and Perrins 1998) (especially in the high Arctic where the habitat is unsuitable for large groups) (Kear 2005a). There is a high degree of synchrony in egg laying and hatching (Johnsgard 1978), with the adults moulting c.10 days after the young hatch (mid-July to mid-August (Scott and Rose 1996)) during which they become flightless for c.21-30 days (Johnsgard 1978, Scott and Rose 1996). Most individuals moult near the breeding grounds (Scott and Rose 1996) although immatures, unsuccessful breeders (Johnsgard 1978) and some more southerly breeding groups (Flint et al. 1984) may undertake pre-moult migrations (Johnsgard 1978) and form large moulting concentrations well-away from nesting areas (Flint et al. 1984). After the post-breeding moult flocks leave the breeding grounds in early-September with some arriving in wintering areas as early as mid-September, others making stopovers on route and arriving later (Madge and Burn 1988). It leaves its wintering quarters again from mid-March to mid-April (Madge and Burn 1988). During the non-breeding season the species remains gregarious, gathering in groups of only a few to several thousands of individuals (Snow and Perrins 1998), although it is rarely found in very large flocks (Kear 2005a). Habitat Breeding The species breeds in coastal Arctic tundra (del Hoyo et al. 1992) in or close to wet coastal meadows with abundant grassy vegetation (Kear 2005a) and on tundra-covered flats with tidal streams (only just above the high tide line) (Johnsgard 1978). In some parts of its range it shows a preference for nesting on small grassy islands (Johnsgard 1978, Madge and Burn 1988, Kear 2005a) in tundra lakes and rivers, especially if nesting Sabine's Gulls Xema sabini (Kear 2005a), Snowy Owls Bubo scandiaca (Flint et al. 1984, Kear 2005a), Peregrine Falcons Falco peregrinus (Flint et al. 1984) or large raptors are present to deter predators (Kear 2005a). High Arctic nesters may also breed widely dispersed over icy tundra, well-away from water (Kear 2005a). Non-breeding Outside of the breeding season the species becomes predominantly coastal, inhabiting estuaries (del Hoyo et al. 1992, Kear 2005a), tidal mudlflats (Madge and Burn 1988, Kear 2005a), sandy shores (del Hoyo et al. 1992), coastal saltmarshes (Kear 2005a) (especially in the spring) (Scott and Rose 1996) and shallow muddy bays (Kear 2005a). In recent years the species has taken to grazing on coastal cultivated grasslands (Madge and Burn 1988, Scott and Rose 1996) and winter cereal fields (Scott and Rose 1996), but rarely occurs on freshwater wetlands except on passage (Madge and Burn 1988). Diet The species is mainly herbivorous (del Hoyo et al. 1992) although it may take animal matter (e.g. fish eggs, worms, snails and amphipods) (Johnsgard 1978). Breeding In its breeding habitat the diet of the species consists of mosses, lichens, aquatic plants (del Hoyo et al. 1992), sedges, tundra grass Dupontia spp., arrowgrass Triglochin spp. and saltmarsh grass Puccinellia spp. (Alaska) (Kear 2005a), although the young may also take insects and aquatic invertebrates (Johnsgard 1978). Non-breeding Outside of the breeding season the species predominantly takes marine microscopic and macroscopic algae (del Hoyo et al. 1992) (e.g. seaweeds, Ulva spp. (Kear 2005a)) and other aquatic plants linked with saline or brackish waters (del Hoyo et al. 1992) in the intertidal zone (e.g. especially eelgrass Zostera spp. (Madge and Burn 1988, Kear 2005a), as well as Ruppia maritima, Spartina alterniflora, Salicornia spp., and arrowgrass Triglochin spp.) (Kear 2005a). Breeding site The nest is a shallow depression (Flint et al. 1984, del Hoyo et al. 1992) on the ground (del Hoyo et al. 1992). Although the species often nests close to water (del Hoyo et al. 1992) typically within a few hundred metres of the tideline (Snow and Perrins 1998), high Arctic nesters may breed on icy tundra well away from water (Kear 2005a) (some nearly up to 10 km inland) (Snow and Perrins 1998) often near boulders where the snow clears first (Kear 2005a). Management information An investigation carried out in one of the species's wintering areas (UK) found that it was most likely to forage on dry, improved grasslands that had high abundances of the grass Lolium perenne, were between 5 and 6 ha in area, and were at a distance of up to 1.5 km inland or 4-5 km along the coast from coastal roosting sites (Vickery and Gill 1999). The species was found to show a preference for grasslands with short, dense swards c.5 cm in height, a characteristic that can be gained through summer management plans involving either mechanical cutting, livestock (sheep or cattle) grazing regimes, or cutting and then grazing (although over longer periods of time the selective grazing of sheep rather than cattle, and frequent rather than infrequent cutting may be more likely to enhance tillering and produce the short, dense sward favoured by this species) (Vickery and Gill 1999). Fertilising the grassland with nitrogen in the autumn at a rate of 50 kg N ha1 was found to increase the overall species use of the habitat by 21 % compared with unfertilised areas (Vickery and Gill 1999), and fertilising at a rate of 75 kg N ha1 was found to increase the overall species use of the habitat by 9-29 % and to remove any preference the geese showed for short sward heights (between 5 and 11 cm) (Vickery and Gill 1999). In other fertilising experiments grazing intensity of the species was found to increase linearly with increasing levels of fertiliser (from 0 kg N ha1 to 150 kg N ha1), although responses in grazing intensity at fertiliser levels lower than 50 kg N ha1 were found to be short-lived (c.2 months after fertiliser application) (Vickery and Gill 1999).

Threats
This species is threatened by hunting (Kear 2005a) and is susceptible to disturbance from vehicles in the UK (Burton et al. 2002) (although it is relatively tolerant of human disturbance, e.g. walkers, compared to other species) (Vickery and Gill 1999, Burton et al. 2002). In its winter range the species may be persecuted by farmers, as in recent years it has increasingly taken to grazing on cultivated grasslands and winter cereal fields near the coast (Scott and Rose 1996). The species may also be threatened in the future by reductions in food supplies following the return of a disease of the eelgrass Zostera marina (a staple food) (Scott and Rose 1996). The nesting success of breeding pairs in Svalbard is greatly reduced as a result of Arctic fox Vulpes lagopus predation (Madsen et al. 1992), and the species is susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006).

References
Brazil, M. 2009. Birds of East Asia: eastern China, Taiwan, Korea, Japan, eastern Russia. Christopher Helm, London.

Burton, N. H. K.; Rehfisch, M. M.; Clark, N. A. 2002. Impacts of Disturbance from Construction Work on the Densities and Feeding Behavior of Waterbirds using the Intertidal Mudflats of Cardiff Bay, UK. Environmental Management 30(6): 865-871.

del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.

Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.

Flint, V. E.; Boehme, R. L.; Kostin, Y. V.; Kuznetsov, A. A. 1984. A field guide to birds of the USSR. Princeton University Press, Princeton, New Jersey.

Johnsgard, P. A. 1978. Ducks, geese and swans of the World. University of Nebraska Press, Lincoln and London.

Kear, J. 2005. Ducks, geese and swans volume 1: general chapters; species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, U.K.

Madge, S.; Burn, H. 1988. Wildfowl. Christopher Helm, London.

Madsen, J.; Bregnballe, T.; Hastrup, A. 1992. Impact of the Arctic Fox Alopex lagopus on nesting success of geese in south-east Svalbard, 1989. Polar Research 11(2): 35-39.

Melville, D. S.; Shortridge, K. F. 2006. Migratory waterbirds and avian influenza in the East Asian-Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK.

Scott, D. A.; Rose, P. M. 1996. Atlas of Anatidae populations in Africa and western Eurasia. Wetlands International, Wageningen, Netherlands.

Sedinger, J. S.; Ward, D. H.; Schamber, J. L.; Butler, W. I.; Eldridge, W. D.; Conant, B.; Voelzer, J. F; Chelgren, N. D; Herzog, M. P. 2006. Effects of El Nino on distribution and reproductive performance of Black Brant. Ecology 87(1): 151-159.

Snow, D. W.; Perrins, C. M. 1998. The Birds of the Western Palearctic vol. 1: Non-Passerines. Oxford University Press, Oxford.

Vahatalo, A. V.; Rainio, K.; Lehikoinen, A.; Lehikoinen, E. 2004. Spring arrival of birds depends on the North Atlantic Oscillation. Journal of Avian Biology 35: 210-216.

Vickery, J. A.; Gill, J. A. 1999. Managing grassland for wild geese in Britain: a review. Biological Conservation 89: 93-106.

Further web sources of information
Detailed species account from Birds in Europe: population estimates trends and conservation status (BirdLife International 2004)

Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Ekstrom, J., Butchart, S., Malpas, L.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Branta bernicla. Downloaded from http://www.birdlife.org on 21/08/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/08/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Brent goose (Branta bernicla) 0

Key facts
Current IUCN Red List category Least Concern
Family Anatidae (Ducks, Geese, Swans)
Species name author (Linnaeus, 1758)
Population size mature individuals
Population trend Unknown
Distribution size (breeding/resident) 360,000 km2
Country endemic? No
Links to further information
- Additional Information on this species