Baikal Teal Anas formosa is listed as Vulnerable under criterion A3c on the basis that the population is projected to decline at a rate of 30-49% over 10 years. Although counts of wintering individuals in South Korea have increased spectacularly over recent years, a decline is projected because it is at risk from poisoning, pesticides and pollution (Degtyarev et al. 2006), large numbers have died in a recent disease outbreak (Degtyarev et al. 2006), its roost sites are unprotected and, most importantly, the dry rice paddies where it feeds are threatened by development and are being converted to vegetable farms and altered for other uses (N. Moores in litt. 2005). There is anecdotal evidence of habitat loss and degradation in the species’s breeding range, and during winter disturbance is an issue, as a significant proportion of the habitats used are now artificial and intensively used by humans (Moores 2005, Degtyarev et al. 2006).
Estimating the global and national populations of this species is problematic because of its tendency to wander in search of lakes and rice paddies extensive enough to support its flocks (Moores 1996). The perceived increase in the population could be partly due to increased observer coverage, and is potentially to some extent due to the shifting of geographic preferences by populations previously wintering in unknown areas of China (Moores 2005). Further evidence, however, suggests that the total population is still increasing (Moores et al. 2010 and references therein). By 2009, census data show that this species was the most numerous waterbird in South Korea, with 1.06 million counted. It is thought that at times this country supports close to 100% of the species’s population. The increase in the South Korean wintering population is believed to be linked to the increase in newly reclaimed land as well as a decline in hunting pressure (Moores 1996, Moores et al. 2010 and references therein).
If this species is indeed increasing, it might be eligible for downlisting. However, the population trend should be estimated for a time period of 20 years (estimate of three generations) and more data and observations are required from other parts of its range to confirm the trend. Further information is also requested on the severity of potential threats and the validity of projecting a future decline.
Degtyarev, A. G., Germogenov, N. I., Heui-Young Kang and Hansoo Lee (2006) Baikal Teal wintering status and distribution in South Korea. TWSG News 15: 77-81.
Moores, N. (1996) Baikal teal in South Korea. In Carey, G. J. ed. Hong Kong Bird Report 1995. Hong Kong: Hong Kong Bird Watching Society. pp. 231-235.
Moores, N. (2005) Baikal Teal Anas formosa. In: Kear, J. ed. Ducks, Geese and Swans. Oxford: Oxford University Press. pp. 605-608.
Moores, N., Kim, A., Park, M.-N. and Kim, S.-A. (2010) The Anticipated Impacts of the Four Rivers Project (Republic of Korea) on Waterbirds. Birds Korea Preliminary Report. Busan: Birds Korea.