Estimation of total numbers of Pied Avocets Recurvirostra avosetta using amoulting site in the Danish Wadden Sea

After the breeding season Pied Avocets Recurvirostra avosetta gather at mou lting sites. Counts show that some of these sites host large parts of the t otal population, but it is not known how many individuals use a particular site over a season (volume of a site). Here we use the method developed by Frederiksen et al. (2001) to calculate the volume of a population of Pied A vocets moulting at Romo (Denmark) in 1993. The results are based on 196 sig htings of 55 Pied Avocets that had been individually marked before the begi nning of the study. The volume was estimated as 10 148 (95% confidence limi ts: 7411 -13 896), which was 49% higher than the peak count (6805 birds). A bout 15% of the East Atlantic Flyway population seemed to use the intertida l mudflats of Romo during the moulting period.