Status of wintering populations of the baikal teal (Anas formosa) in Geumgang River, Korea

This study investigated the daily changes of individual numbers of the baikal teal migrating in Geumgang River from November in 2008 to March in 2009 and from November, 2011 to February, 2012. The finding from 2008 to 2009 showed that the highest number of 500,000 individuals (November, 2008) with an average of 146,582 ± 123,705 individuals were recorded. The finding from 2011 to 2012 indicated that the highest number of 250,000 individuals (January, 2012) with an average of 61,696 ± 63,407 individuals. The baikal teal's population was increased in the early wintering period was not observed in the mid-wintering period when the Geumgang River became frozen. On the other hand, the population tended to increase again in the late wintering period when the river began to thaw. As the baikal teals prefer flat water areas without currents, they were mainly observed in the upper stream of Geumgang estuary barrage but not in the downstream.