Visitation Aspect of shorebirds (Tringa spp.) in the Nakdong Estuary, Busan

This study was conducted at Nakdong Estuary in Busan Metropolitan City. The study aimed to monitor Tringa spp. at Nakdong Estuary through the comparative analysis of the long-term findings between the early 1990s (May, 1989~April, 1993) and the mid-2000s (May, 2002~April, 2008). During the research period (May, 1989~April, 1993, May, 2002~April, 2008: 10 years in total), the total of 116,761 birds representing 9 genera, 27 species were observed. Of them, the total number of Tringa genus of family Scolopacidae was 1,461 individuals (1.25%) representing 7 species, including 150 individuals of Tringa erythropus, 24 individuals of Tringa totanus, 28 individuals of Tringa stagnatilis, 1,223 individuals of Tringa nebularia, 9 individuals of Tringa guttifer, 24 individuals of Tringa ochropus, and 3 individuals of Tringa glareola. The monthly comparison of the visitation of the genera Tringa between two periods, there was no significant difference between the individual numbers in the early 1990s and the mid-2000s (P>0.39). There were more individuals observed in the early 1990s (Mean=163.00) than those in the mid-2000s (Mean=134.83). The results of monthly number of individuals in each year between the early 1990s and the mid-2000s (from May to April in following year) indicated that there was statistically significant mean difference in May (P>0.01). On the other hand, no statistical significance was found in the other months. The means of the individual numbers observed in the mid-2000s appear in Table 3 and Fig 3. As Table 3 indicates, the mean of individual number of five sites was 26.97: 57.33 individuals in Daema-deung (DMD), 11.83 individuals in Jangja and Shinja-Do (JJ & SJD), 7.33 individuals in Saja and Doyo-deung (SJ & DYD), 8.00 individuals in Lower Ulsuk-Do (LUD), 50.33 individuals in Ulsuk-Do (USD). There was statistically significant mean difference among these five sites (P>0.01).