|Habitat and Ecology:
Behaviour This species is fully migratory (del Hoyo et al. 1992), travelling on a narrow front (Kear 2005a) between separate breeding and wintering grounds (del Hoyo et al. 1992). It breeds from mid-May to late-June or early-July (Kear 2005a) in territorial pairs (Madge and Burn 1988) which may form loose colonies (Madge and Burn 1988, del Hoyo et al. 1992) of not more than c.10 pairs (Snow and Perrins 1998). After breeding the species undergoes a flightless moulting period in July and August that lasts for c.25 days (Scott and Rose 1996), during which it remains close to open water (such as the sea or early thawing lakes) (Kear 2005a). Icelandic non-breeding flocks migrate to staging areas (Madge and Burn 1988, Kear 2005a) in east Greenland to moult, whereas breeding birds from Svalbard, Greenland and Iceland remain near their breeding areas (Scott and Rose 1996). After moulting the species departs from its breeding and staging grounds (Kear 2005a) from August to mid-September (Madge and Burn 1988), most arriving on the wintering grounds in October (Madge and Burn 1988). Outside of the breeding season the species remains highly gregarious (Madge and Burn 1988), generally forming large concentrations in the autumn (commonly up to 5,000 in the UK) (Snow and Perrins 1998) and in winter (Madge and Burn 1988). These aggregations are usually loose however, with large roosting flocks dispersing into smaller foraging groups by day (Snow and Perrins 1998). During the winter the species roosts on water by night and forages in nearly all hours of daylight (Kear 2005a). Habitat Breeding The species breeds on rocky outcrops, crags, steep river gorges (del Hoyo et al. 1992, Kear 2005a), cliffs, riverbanks and snow-free hummocks near areas of lush vegetation (Greenland) (Kear 2005a) in open arctic tundra (del Hoyo et al. 1992), especially near seabird colonies (Kear 2005a). Later in the summer the species forages chiefly on damp sedge-meadows, and while moulting and flightless it remains close to the sea or early-thawing lakes (Kear 2005a). Non-breeding The species overwinters on extensive areas of saltmarsh (Madge and Burn 1988, Kear 2005a) in estuaries (del Hoyo et al. 1992) and on flat agricultural land (del Hoyo et al. 1992) (e.g. improved or fertilised grasslands, stubble fields, pastures and newly sown cereal fields) (Kear 2005a). In Scotland favoured winter daytime roosting sites include estuarine mudflats, lochs and reservoirs (Madge and Burn 1988). Diet The species is hebivorous (del Hoyo et al. 1992) and an opportunistic forager (Kear 2005a). Breeding During the breeding season its diet consists of the leaves, stems, roots, berries and seed-heads of sedges, mosses, lichens (del Hoyo et al. 1992), Empetrum spp. and grasses (Kear 2005a). Non-breeding In its wintering areas the species is more reliant on grass, grain, vegetables (e.g. carrots, sugar beet (Kear 2005a)) and potatoes grown on agricultural land (del Hoyo et al. 1992). Breeding site The nest is a low mound of vegetation (del Hoyo et al. 1992, Kear 2005a) on cliffs, rocky outcrops or snow-free hummocks (Kear 2005a) often near seabird colonies (Kear 2005a). The species nests in territorial pairs (Madge and Burn 1988) which may from loose colonies (Madge and Burn 1988, del Hoyo et al. 1992) of not more than c.10 pairs, with neighbouring nests spaced as little as 5 m apart (usually more than 75 m apart) (Snow and Perrins 1998). Management information An investigation carried out in one of the species's wintering areas (UK) found that it was most likely to forage on grasslands a minimum of 6 ha in area, managed by livestock grazing or mechanical cutting, with an optimum sward height of 13-20 cm (although the species was also found to use heavily grazed land down to a sward height to 1.5 cm), at a distance of less than 10 km away from roosting sites (the optimum distance was 2-5 km away) (Vickery and Gill 1999). Fertilising the grassland with nitrogenous fertiliser (ammonium nitrate 34.5 % N) in early-March at a rate of 80 kg N ha1 was also found to double the grazing intensity of geese compared to unfertilised areas (although no further increases were found with higher rates of fertiliser application) (Vickery and Gill 1999). Studies in the Vejlerne nature reserve, Denmark found that wind turbines placed in lines or small clusters cause less disturbance to the species than large clusters (small clusters may be placed in conjunction with existing physical elements such as roads, wind-breaks or buildings, and are therefore less likely to coincide with grasslands areas used for grazing by the species) (Larsen and Madsen 2000).