Swan Goose Anser cygnoides Scientific name definitions

80–94 cm (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); male c. 3500 g, female 2850–3450 g (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); wingspan 165–185 cm (2 Brazil, M. (2009). Field Guide to the Birds of East Asia: Eastern China, Taiwan, Korea, Japan and Eastern Russia. Christopher Helm, London, UK. Close ). Easily recognized by pattern and shape of head and bill  . Female slightly smaller with shorter bill and neck. Juvenile  lacks white band around bill and flank markings; irides duller (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); upperparts dull greyish brown.

• Graylag x Swan Goose (hybrid) Anser anser x cygnoides
• Swan Goose x Canada Goose (hybrid) Anser cygnoides x Branta canadensis

C Asia from SC Siberia to Mongolia and N China; recorded in E Kazakhstan and Turkmenistan and breeding is suspected in NE North Korea (4 BirdLife International (2013). IUCN Red List for birds. URL: http://www.birdlife.org (download Aug 2013). Close ). Winters in North Korea, South Korea, CE China, and occasionally in Japan and Taiwan.

Varied, generally in close association with water, brackish or fresh (rivers or lakes) (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); also in mountain regions, steppes and floodplains. Breeds in reedbeds along rivers, on grassy hillocks in marshy meadows or on grassy plateaux. In winter and on passage found on drier ground, often on barren steppes well away from water, but principally spends winter at brackish and freshwater lowland marshes, plus wet cultivated areas such as rice fields (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ) and tidal mudflats.

Migratory, winters mainly in E China and in Korea, formerly also in Japan where now very rare. First movement, starting in late Aug, away from breeding grounds is usually to lower areas, whereupon forms flocks and migration S commences in mid Sept, though some remain in vicinity of breeding grounds until early Oct, although timing of arrival on winter grounds is unclear (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). In spring, generally departs wintering areas in late Mar, arriving on breeding grounds in early–mid Apr (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Migration routes not well studied as yet, and such information is much needed given the large disconnect between knowledge of the species’ breeding grounds and the huge numbers recorded in winter in China  ; however, recent data from Sakhalin indicate that larger numbers of geese in general (specific numbers of A. cygnoid unrecorded) have been passing through the island since 2005 and that their preferred route has tracked eastwards, apparently due to changes in climatic conditions (5 Tiunov, I. M., A. Y. Blokhin, and P. A. Faiman (2011). Routes and intensity of geese migration over northern Sakhalin and the mainland part of Tatar Strait. Russian Journal of Ecology 42(2):151–160. Close ). Vagrant to NW Thailand, N Laos (same record) (6 Robson, C. (2000). A Field Guide to the Birds of South-east Asia. New Holland, London, UK. Close ), Taiwan  , Kazakhstan (six records, 1900–1967, other than breeding occurrences) (7 Wassink, A., and G. J. Oreel (2007). The Birds of Kazakhstan. Published privately, De Cocksdorp, Texel, The Netherlands. Close ), Turkmenistan (Sept 2005), Uzbekistan (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ) and SE Siberia (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

Almost exclusively vegetarian diet, partly consisting of sedges, but comparatively few data. In summer grasses are apparently important, with stomach contents of ten birds from Amur basin almost exclusively Carex, while non-breeders that fed along Sakhalin coast at this season fed on meadows, mainly taking Carex subpathacea, but also fruits of Oxycoccus, Vaccinium ovalifolium and Empetrum sibiricum, as well as needles of Larix ochotensis (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). In winter, at freshwater marshes, preferentially takes roots of Vallisneria asiatica and on canary grass (Phalaris arundinacea), whereas at brackish sites seeds of Suaeda salsa are apparently single most important item, with rice also being selected in some areas (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Often grazes on dry land, especially on migration (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Flock size varies seasonally: up to c. 40 birds in spring, non-breeding summer flocks up to 200 and moulting flocks slightly larger (exceptionally up to 1000), and largest in winter (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

Commonest vocalization is a prolonged, resounding, ascending honk  , whereas “Triumph Display” is low cackling “gangangangang”, alarm is a harsh, short note repeated 2–3 times, and pre-flight gives a low “ga-ga-ga-ga-ga” (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

Starts latter half of Apr, sometimes not until late May (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); hatching mainly late May/June and most young have fledged by late Aug (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Pair formation probably commences in winter and species is long-term monogamous (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). In loose groups or scattered pairs in favoured areas, e.g. at least formerly, up to 170 pairs at L Udyl and 1200–1300 pairs along 35 km of coast between Capes Tyk and Lakh (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); female (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ) builds shallow nest of plant matter on ground, 255–320 mm in diameter and 40–65 mm deep, lined with dry grasses and down, and usually sited in dense vegetation (Carex or Ledum palustre thicket), or on island (often adjacent to gull Larus colony) or in steppe grass, but almost invariably close to water (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Usually 5–6 white eggs (4–8) (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ), size 73–92·7 mm × 45·6–57·5 mm, mass 117·6–159 g (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); incubation c. 28 days (in captivity) by female alone, guarded by male, who also assists her to rear young (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); chick has yellowish-buff head and underparts, broad blackish eye-patch, dusky brown upperparts with pale buff patches and blackish-grey bill with pale tip (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ); cygnets form small crèches of up to 60 birds, but no data on fledging period (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Study on introduced population in SW Germany found that division of labour between sexes during brood-rearing period was similar to that in wild Anser populations: males were more vigilant whereas females spent more time feeding during first four weeks of brood-rearing, while as brood-rearing progressed, vigilance and agonistic behaviour by both sexes decreased, whereas juveniles decreased feeding and increased vigilance (8 Randler, C. (2007). Parental investment in Swan Geese in an urban environment. Wilson J. Orn.. 119(1): 23-27. Close ). Sexual maturity at 2–3 years.

VULNERABLE. Previously considered Near Threatened, and was briefly uplisted to Endangered in early 2000s. Legally protected in Russia, Mongolia  , South Korea and some provinces in China, while several important sites are protected in Russia, Mongolia and China (e.g. Dalai Nur National Nature Reserve (9 Wang, T., and S. So (2003). Waterbirds spending the boreal summer at Dalai Nur National Nature Reserve, Inner Mongolia, China. Bulletin of the Oriental Bird Club 38:58–61. Close ), Yancheng Nature Reserve) (10 Benstead, P. (2002). Conservation Fund: The conservation of threatened birds and their habitats at Yancheng marshes, Jiangsu, China. Bull. Oriental Bird Club. 36: 13. Close ). Population estimated at 30,000–50,000 individuals in late 1990s, even 50,000–60,000 in early 2000s (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ) and most recently 60,000–90,000 individuals, with a flock of 61,650 at Poyang Hu in 2002, 60,886 in winter 2002/2004 in the lower Yangtze Valley (11 Barter, M., L. Cao, L. Chen, and G. Lei (2005). Results of a survey for waterbirds in the lower Yangtze floodplain, China, in January–February 2004. Forktail 21:1–7. Close ) and, in Jan 2011, 87,544 were counted at the most important Yangtze R wetlands, with 25,502 at L Neizhu and Waizhu, 21,000 at L Hanchi and 19,763 at Poyang Lake National Nature Reserve. Furthermore, totals of 33,000 and 12,000 birds in E Mongolia during surveys in 2003 and 2004, respectively. Global population suspected to have decreased rapidly, in line with levels of hunting and wetland conversion for agriculture and development, with these threats operating on breeding and wintering grounds; the increased population estimate following surveys in Jan 2011(above) is unlikely to represent an actual increase. Four main breeding areas generally recognized: (1) in W & C Mongolia (N of Gobi Altai), possibly in neighbouring Tuva (R Tes-Khem and L Tere-Khol) and NW China (N Xinjiang); (2) L Torei in Chita Oblast (Russia), NE China (W Heilongjiang, NW Jilin and N Inner Mongolia) and possibly E Mongolia; (3) L Khanka (Russia); and (4) L Udyl and Schastye Bay (Amur basin) and N Sakhalin (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Range has contracted (formerly reached S Baikal and E through N Amur, sporadically W to Minusink depression and E Kazakhstan, where might still persist around L Saisan) (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ) and numbers have fallen during present century, for example, probably fewer than 100 pairs on Sakhalin (versus well over 1000 pairs in early 1950s) and breeding unconfirmed at L Khanka since 1976 (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Only recent record from Buryatia, S of L Baikal, dates from Jun 2001 and last indication of breeding there is from 1970s (12 Tebb, G., and A. Ranner (2002). New significant bird records from Buryatia, Russia. Forktail 18:101–105. Close ), while species is now only a vagrant at L Baikal itself (13 Mlíkovský, J. (2009). Waterbirds of Lake Baikal, eastern Siberia, Russia. Forktail 25:13–70. Close ). Population in former USSR was reckoned to number no more than 300–400 pairs. Largest numbers elsewhere include: 1000 birds in Ogii Nuur, NC Mongolia, in Jun/Jul 1977, and 35,000 at Yancheng Marshes, EC China, in Jan 1988. Declines appear to be continuing throughout Anhui province, for instance, with numbers wintering at L Shengjin declining from 10,000–20,000 birds in 2003–2006 to just c. 1000 by winter of 2008/09, probably owing to reductions in submerged vegetation (14 Yong Zhang, Lei Cao, Barter, M., Fox, A.D., Meijuan Zhao, Fanjuan Meng, Hongquan Shi, Yong Jiang and Wenzhong Zhu (2011). Changing distribution and abundance of Swan Goose Anser cygnoides in the Yangtze River floodplain: the likely loss of a very important wintering site. Bird Conservation International. 21(1): 36-48. Close ). Formerly up to 100 wintering in Japan, but continual decrease due to habitat loss culminating in extinction around 1950. Now irregular winter visitor to Japan in insignificant numbers, but up 1858 birds at Hang estuary, South Korea, in Mar 1994 (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Severe hunting pressure and habitat destruction at breeding grounds have seriously affected W populations. In Russia, main threats uncontrolled hunting, drainage and ploughing of breeding and moulting habitats, and disturbance by people and cattle, which also cause high levels of chick mortality; in China, agricultural development at breeding grounds has resulted in wetland destruction and increased disturbance, while egg collection on Sanjiang plain, coupled with habitat loss to agricultural development, has probably resulted in a decline in  numbers of breeding Anatidae of 90% in last 30 years, and recent droughts on breeding grounds have resulted in several years of poor recruitment. Furthermore, the species is absent from many suitable areas probably because of disturbance caused by motor-boats and other high-speed vessels, as well as illegal hunting activity. Hunting of waterfowl is reported to be increasing in Mongolia in recent years. Its wetland wintering grounds are under increasing pressure from development and pollution: the species is becoming more concentrated at fewer key wintering localities, especially Poyang Hu, which itself is subject to large between-year changes in hydrological conditions (resulting in inundated areas varying four-fold since c. 2002) and has been proposed for damming, while the concentration of birds at fewer sites in winter renders the species more susceptible to the impacts of pollution, disease and hunting (14 Yong Zhang, Lei Cao, Barter, M., Fox, A.D., Meijuan Zhao, Fanjuan Meng, Hongquan Shi, Yong Jiang and Wenzhong Zhu (2011). Changing distribution and abundance of Swan Goose Anser cygnoides in the Yangtze River floodplain: the likely loss of a very important wintering site. Bird Conservation International. 21(1): 36-48. Close ).