Numbers and population trends of waders along the Belgian North Sea coast

As part of the international Europe-NEWS project in 1997/98, two wader counts were organised along the entire length (65.4 km) of the Belgian North Sea coast. The total number of waders varied between 3,964 in December and 4,871 in January. The average numbers of the species recorded were: 1,433 Eurasian Oystercatcher Haematopus ostralegus , 63 Pied Avocet Recurvirostra avosetta, 14 Common Ringed Plover Charadrius hiaticula, 264 Grey Plover Pluvialis squatarola, five Red Knot Calidris canutus, 377 Sanderling C. alba, 111 Purple Sandpiper C. maritima, 888 Dunlin C. alpina, one Black-tailed Godwit Limosa limosa, 41 Bar-tailed Godwit L. lapponica, 90 Eurasian Curlew Numenius arquata, one Spotted Redshank Tringa erythropus, 87 Common Redshank T. totanus and 1,045 Ruddy Turnstone Arenaria interpres. Placed in an international context, coastal wader populations in Belgium are rather small and do not represent a large proportion of the total biogeographic populations. The most important species is Ruddy Turnstone, with 0.7% of the biogeographic population. Since the first wader counts took place in the 1970s, midwinter numbers of many coastal wader species in Belgium have shown clear trends. When the 10 most common species are examined, six show an increasing trend (Eurasian Oystercatcher, Pied Avocet, Grey Plover, Dunlin, Common Redshank and Ruddy Turnstone) and four have decreased in number (Common Ringed Plover, Sanderling, Purple Sandpiper and Eurasian Curlew). Possible reasons for the observed trends are discussed.