Justification of Red List Category
This species is listed as Vulnerable because it has suffered a rapid population reduction in its key breeding populations in Russia, and equivalent declines are predicted to continue. The Fennoscandian population has undergone a severe historical decline, and has not yet recovered.
The most recent total population estimate is 24,000-40,000 individuals, which compares with previous published global estimates of 25,000 to 30,000 individuals (Lorentsen et al. 1999) and 22,000 to 27,000 (Delany and Scott 2006). This includes 10,000-21,000 individuals in autumn in its Western Palearctic range (Jones et al. 2008, Fox et al. 2010) and 14,000-19,000 individuals from the East Asian Flyway (Jia et al. 2016, C. Lei per A. Fox in litt. 2016). In 1988-1993, 64,000 individuals were recorded (Jia et al. 2016); in 1997, the number declined to 20,000 individuals (Li and Mundkur 2004), and to less than 17,000 individuals (Morozov and Syroechkovski 2005): 16,937 birds were counted in the Lower Yangtze Valley in 2004 (Barter et al. 2004), and 16,600 in East Dongting Lake Nature Reserve in 2004 (Barter 2005). The Russian populations have declined from a former estimate of 30,000-50,000 individuals (Morozov 1995). The Fennoscandian population has declined from more than 10,000 birds in the early 20th century.
This species's population is suspected to have decreased rapidly, owing to high levels of hunting on the staging and wintering grounds and habitat deterioration, largely as a result of land cultivation. The decrease in numbers has been accompanied by fragmentation of the breeding range and is continuing to affect all populations. Modelling indicates that 28% of the habitat for this species could be lost by 2070 (Zöckler and Lysenko 2000).
Four subpopulations of Anser erythropus can be recognised. Three of these are surviving components of the species’s formerly extensive breeding range: the Fennoscandian population which breeds in the Nordic countries (Norway 20-25 pairs, Finland 0-5 pairs, Sweden 15-25 pairs,which has been reinforced by reintroductions (BirdLife International 2015) and the Kola Peninsula in Russia; the Western Asian main population which breeds in northern Russian tundra to the centre of the Taimyr Peninsula, including Putorana Plateau, and to the west and east of Pechora and Western Siberia (Yamal and Gydan peninsulas); and the Eastern Asian main population which breeds in the southern Taimyr and areas north of Eastern Siberia and Chukotka. Fennoscandian breeders overwinter at Kerkini Lake and in the Evros Delta between Greece and Turkey (Lorentsen et al. 1998). A small wintering population is also now established in The Netherlands, which originates from the reintroduced breeding population in Sweden. Birds from the Western Asian main population winter around the Black and Caspian Seas, mainly in Azerbaijan, Iraq, Iran and Uzbekistan (V. Morozov in litt. 2016, N. Mikander, I. Øien and T. Aarvak in litt. 2016); and birds from the Eastern Asian main population winter in the Yangtze River Valley in China (following considerable range contractions in this country; A. Fox in litt. 2016), the Korean Peninsula and in Japan (N. Mikander in litt. 2016). Fennoscandian breeding birds occur on passage mainly in Finland, Estonia and Hungary, while many non-breeders migrate through Russia and Kazakhstan (Tolvanen et al. 1999, Aarvak and Øien 2003, Morozov and Syroechkovski 2005), and in smaller numbers in Lithuania, Slovakia, Romania (Munteanu et al. 1991, Aarvak et al. 1997) Bosnia and Herzegovina, Albania, and Bulgaria (Petkov et al. 1999). Birds from the Western Asian main population occur during passage mainly in Kazakhstan, but also Syria, Turkmenistan, Ukraine, and Uzbekistan (Jones et al. 2008); and birds from the Eastern Asian main population possibly stop-over in Mongolia (A. Bräunlich in litt. 2011, N. Mikander in litt. 2016). Due to limited genetic introgression of Greater White-fronted Goose genetic material in the reinforced Swedish population, some concerns have been raised about whether that population should be considered in the current Red List assessment. The current Guidelines for Using the IUCN Red List Categories and Criteria (Version 11, February 2014) do not provide any guidance on what levels of hybrid gene frequency are acceptable to allow inclusion of populations of released birds from captive breeding programmes in a Red List assessment. However, a global assessment of Red List Category is not affected by this debate.
Behaviour This species is fully migratory, and information about its migration routes has only recently come to light as a result of satellite telemetry studies and increased monitoring efforts (Lorentsen et al. 1998, Aarvak and Øien 2003, Kear 2005). The species departs from its breeding grounds in northern Scandinavia and Arctic Russia in late August to early September. The Fennoscandian population follows several routes: either south (through Hungary), or east and then south, through the Russian Taimyr Peninsula in northern Siberia, northern Kazakhstan and finally the Black Sea (Snow and Perrins 1998, Øien et al. 2005), to reach wintering grounds in south-east Europe. The West Asian main population migrates mainly south along the Ob River Valley in Russia, via the same staging grounds in northern Kazakhstan to wintering grounds in Azerbaijan and the Middle East (around the Caspian Sea and the Persian Gulf) (Alerstam 1990, Snow and Perrins 1998). The East Asian main population winters in eastern China and the Korean peninsula (del Hoyo et al. 1992, Madsen 1996) as well as increasingly in Japan (some 100 individuals; T. Ikeuchi per N. Mikander in litt. 2016). The return passage to the breeding grounds begins in February, with the species arriving from early May to late June (Madsen 1996, Snow and Perrins 1998). In Siberia, non-breeding birds undertake a moult-migration to higher altitudes or to areas north of the breeding range (Madsen 1996) and non-breeders or failed breeders from the Fennoscandian population migrate eastwards and join these flocks before the onset of moulting (Aarvak and Øien 2003). Evidence indicates that this species is not a colonial breeder (Johnsgard 1978), but nests in pairs on isolated territories (Madge and Burn 1988). However, the species is gregarious outside the breeding season (Madge and Burn 1988).
Habitat Breeding This species breeds in low-lying bogs, scrub-covered tundra and taiga-forest edges close to wetlands, up to 700 m above sea level (Kear 2005). It can also be found on the slopes by lower parts of mountain streams, on mountain foothills, mountain lakes and on alpine precipices, often in thawing boggy areas or on stonefields (Cramp and Simmons 1977, Johnsgard 1978). Adults of this species undergo a post-breeding flightless summer moult whilst still in their breeding range. In Siberia and Fennoscandia, non-breeding adults migrate to areas north (West Asian main) or east (Fennoscandian) of the breeding range or to higher altitudes to exploit large open water fringed with sedge (Carex), or river valleys with long grass and scrub to escape predation (Aarvak and Øien 2003, Kear 2005). Non-breeding During winter and on migration, this species frequents open short grassland in the steppe and semi-arid zones, particularly in sodic (e.g. seashore) pastures, arable farmland, pastures and meadows (Cramp and Simmons 1977, Madsen 1996, Kear 2005). Winter roosting colonies are also formed on large lakes and rivers, or in reedbeds and rushes (Cramp and Simmons 1977, Madge and Burn 1988).
Diet This species is herbivorous, feeding on grasses, roots, stems, leaves, fruits and the green parts of aquatic and terrestrial plants along lake-shores, rivers and marshes (Kear 2005). During the winter the species supplements its diet with winter agricultural grains (Kear 2005).
Breeding site Birds of this species often nest on snow-free patches available early in the breeding season (such as rocky outcrops or prominent hummocks) hidden amongst vegetation (grass, dwarf shrub heathland) or in boggy hollows (Madsen 1996, Kear 2005), usually in close proximity to open water or marshy areas (Kear 2005).