Patterns of occurrence of waders (Aves, Charadrii) in the Axios Delta, Macedonia, Greece

VASSILIS GOUTNER^1*, SAVAS KAZANTZIDIS² and IRIS CHARALAMBIDOU³

1 Department of Zoology, School of Biology, Aristotle University, 54124 Thessaloniki, Greece
2 National Agricultural Research Foundation, Forest Research Institute, 57006 Vassilika, Thessaloniki, Greece
3 Birdlife Cyprus, P.O. Box 280716, 2090 Lefkosia (Nicosia), Cyprus

Abstract

In the Axios Delta, northern Greece, thirty one species of waders were recorded from January to December 1990. Most species presented population peaks that indicated characteristic temporal patterns of occurrence in the area. The highest total numbers were observed in the winter, early spring and in mid-summer. The number of species varied from 10 to 24 and was not correlated to total population size (r_s=-0.311, n.s.). Some populations of species dominated on two or three successive visits, but dominance changed over time. Total wader numbers were negatively correlated with average tide heights (r_s=-0.685, p=0.0002), probably because the lack of safe roosting sites at high water forced part of the population out of the area. Cluster analysis revealed that wader species in the Axios Delta were grouped according to their seasonal pattern of occurrence. The same analysis of spring population trends, including data from other Greek coastal wetlands, showed a strong association of counts in monthly groups. Analyses suggest that the occurrence of wader populations in the Axios Delta follows wider regional patterns. The geographical position of Greek coastal wetlands along the eastern Mediterranean flyway makes them more useful to waders in the winter and during spring migration. Wader populations in the Axios Delta would benefit from artificial flooding and the regulation of grazing in the lower delta during the summer. The Axios Delta exceeds 14.1 times the criterion of 1% as a key site for wintering waders on a national level and also constitutes an internationally important staging area.