Visitation Characteristics of Shorebirds (Numenius spp.) in the Nakdong Estuary, Busan, R.O. Korea

This study was conducted to understand the variation of the visitation aspect of shorebirds (Numeniuss spp.) between1990s and 2000s in the Nakdong estuary, Korea. The dataset was collected through two long-term monitoring sessions: one in the early 1990s (May 1989~April 1993) and other in the mid-2000s (May 2002~April 2008). During these two periods, 3 species and 21,009 individuals of shorebirds were observed: 16,965 Eurasian curlew (N. arquata), 2,640 Eastern curlew (N. madagascariensis), and 1,404 Whimbrel (N. phaeopus). The observed individuals were larger in the mid-2000s than in the early 1990s; also there was a significant difference in the number of individuals between the two periods. The Whimbrel individuals were larger in the early 1990s than in the mid-2000s. The average number of the observed individuals in five different regions was as follows: 739 in Daemadeung, 1,009 in Jangja·Shinjado, 433.17 in Saja·Doyodeung, 362.83 in Lower Ulsukdo, and 22.17 in Ulsukdo; the total average of these 5 regions was 513.23. There was a significant difference in size of individual numbers among the monitored regions. In particular, the observed individuals were larger in Jangja-Shinjado and Daemadeung than in other regions.