Autumn Migration of Waders (Charadrii) at the Reda Mouth (N Poland)

The migration of waders was investigated at the Reda mouth (Polish Baltic coast) between 1996 and 2001. During the study 496 counts were conducted in the period between 5 July and 5 October. The most numerous species observed were: the Lapwing (Vanellus vanellus) - 39.5% and Dunlin (Calidris alpina) - 29.8% of all waders. Because of a variety of habitats in the Reda mouth region, among the waders staging numerously in the Reda mouth there were species typical both for coastal and inland habitat. It was shown that birds from tundra zone migrated later than those from more southern breeding areas, which was caused by much later beginning of egg laying in northern latitudes. Moreover, in the species from tundra zone, e.g. the Knot (Calidris canutus), Little Stint (C. minuta), Curlew Sandpiper (C. ferruginea), the migration of both age classes were well separated, whereas in those from more southern areas, e.g. the Little Ringed Plover (Charadius dubius), Common Sandpiper (Actitis hypoleucos), such difference was less pronounced and the period of common passage of adults and juveniles was much longer. A comparison of the obtained data on migration pattern with some other sites in Poland where regular counts were conducted showed several similarities and some discrepancies, which are discussed in the paper.