Archived 2010-2011 topics: Baikal Teal (Anas formosa): request for information

Link to BirdLife species factsheet for Baikal Teal

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.

This entry was posted in Archive, Asia, Waterbirds and tagged . Bookmark the permalink.

4 Responses to Archived 2010-2011 topics: Baikal Teal (Anas formosa): request for information

  1. Andy Symes says:

    Nial Moores provided the following information (February 2010):

    The continued increase in the population of Baikal Teal Anas formosa counted wintering in the Republic of Korea means that we believe that the species can no longer be considered Vulnerable.

    A national one-day census of birds in January, conducted annually since 1999, and coordinated (and published) by the national Ministry of Environment (MOE 1999-2004,2005,2006,2007,2008,2009) reveals a rapid upward trend in the species, with large flocks now present at a number of sites.

    The species remains highly nomadic in winter (meaning that counts can vary enormously year to year and site to site) and the number of count sites for the census has increased each year, to more than double over a decade. Nonetheless, the 2-year mean of counts nationwide reveals an obvious upward trend:

    99-00 212273
    01-02 236529
    03-04 379167
    05-06 304211
    07-08 723087

    In January 2009 (2010 counts are not yet published) a total of 1,063,280 were counted nationwide, with concentrations of >20,000 recorded at six different sites.

    There is no doubt now that this increase in numbers is genuine, and is not based (only) in increased count effort or sites covered.

    To support this assumption, Birds Korea’s analysis of counts conducted at 38 sites which have been censused each year since 1999 (selected for a paper on the impacts of the Four Rivers Project) also show a rapid increase in number of Baikal Teal at these sites, from a mean of 11,533/year (1999-2003), to a (staggering!) mean of 314,994/year (2005-2009).

    As suggested in earlier publications (e.g. Moores 1996, Moores, N. 2005), it appears that the continued increase in area of reclamation lake favored by the species for roosting, as well as the decline of (illegal) hunting, has helped the population to increase rapidly – both in number and also in popularity with sight-seers.

    While we consider that the species is happily no longer globally threatened, threats remain that could reverse some/much of the increase of the past two decades, most especially disease, habitat loss and increased disturbance. Most sites used by the species are still unprotected, and many remain threatened by further infrastructure development and increased disturbance.

    Future conservation efforts might best focus on reducing disturbance at key sites and finding ways to win local farmers’ support for the conservation of this and other rice-field species. Further research might also be valuable into food availability for this and other species , to identify likely carrying capacity as the area of rice-field declines. This would be helpful for the Baikal Teal and also to assess the significance (if any) of competition with other species (cf Allport et al., 1991). Of note, the Ministry of Environment Census data also reveal a steady and rather worrying decline in the Mallard during the same period (of ca. 50%). This is a more generalist species, that often nonetheless also roosts on lakes to feed in rice-fields at night.

    Nial Moores,on behalf of Birds Korea


    Allport G., Poole C., Park E-M.& Jo S-R. 1991. The feeding ecology, requirements and distribution of Baikal Teal (Anas formosa) in the Republic of Korea. Wildfowl 42: 98-107.

    Ministry of Environment Winter Bird Site Census, 1999-2004,2005,2006,2007,2008,2009.

    Moores, N. 1996. Baikal Teal in South Korea. Hong Kong Bird Report 1995: 231-235

    Moores, N. 2005. Baikal Teal Anas formosa. In: Kear J. (Ed.). Ducks, Geese and Swans. Oxford University Press, Oxford, UK, pp. 605-608.

  2. Andy Symes says:

    Mark Barter provided the following information (February 2010):

    Numbers have definitely been increasing in China during recent years, presumably due to emigration from South Korea. During the last few days we have counted 5,494 in Anhui at a number of sites in 5 large wetlands; flocks ranged from 161 to 4,000 in size. In earlier years flocks as large as 8,000 and 50,000 have been located elsewhere in east China. We have recently seen Baikal Teal in Jiangxi and Jiangsu provinces.

    With Baikal Teal now returning to China and being apparently widespread, previous concerns about the range being basically limited to a few sites in South Korea are greatly diminished and this adds strength to the suggestion by Nial Moores that the species is no longer Vulnerable.

    Lei Cao and Mark Barter
    University of Science and Technology of China

  3. Baz Hughes says:

    I agree that Baikal Teal should be downlisted.

    Best wishes


  4. The population of Baikal Teal Anas formosa in Japan is not increasing as much as that of the Republic of Korea.

    In Japan, annual survey of ducks, swans and geese have been conducted by the Ministry of Environment of Japan since 1967.
    The number of Baikal Teal recorded in the national survey are;

    average number in 1970s = 13157
    (maximum number is 36918 in 1970)
    ave. in 1980s = 4557
    ave. in 1990s = 1423
    ave. in early 2000s = 2650
    2005 = 1661
    2006 = 2032
    2007 = 3144
    2008 = 12212
    2009 = 4131

    It may also be increasing in Japan, but the rate of increase is very low compared with that of the Republic of Korea. I think the rapid growing of the population of Baikal Teal may occur regionally.

    If the growth of the population may continue, it should be downlisted. But when I consider the disparity in the Korean and Japanese population of Baikal teal, it may be too early to downlist.

Comments are closed.