EXPERIMENTAL REFUGES FOR MIGRATORY WATERFOWL IN DANISH WETLANDS - I -BASE-LINE ASSESSMENT OF THE DISTURBANCE EFFECTS OF RECREATIONAL ACTIVITIES

1. Potential human sources of disturbance, including fishing, sailing, windsurfing and different types of waterfowl hunting, are described a nd their effects on autumn-staging waterbirds, including mute swan, wi geon and coot, were examined at a coastal wetland in Denmark from 1985 to 1988. 2. Bird and human distributions were superimposed on the dis tribution of submerged vegetation and water depths to identify the ext ent of spatial overlap; likewise, seasonal and diurnal temporal overla p in bird abundance, and human activities were defined. Behavioural an d distributional reactions of waterbirds to different human activities , in terms of escape distances, disruption of activity patterns and re distribution, were assessed to establish their relative effects. 3. Sa iling and windsurfing showed little spatial overlap, and fishing parti al spatial overlap with bird distributions; these activities almost ce ased before the peak in autumn bird numbers. Hunting showed a high deg ree of spatial and temporal overlap with bird presence. 4. Birds respo nded to windsurfing at greatest distances, whereas hunting (especially from mobile punts) caused the longest disruptions to activities of wa terfowl. In terms of behaviour and redistribution, wigeon was more aff ected by shooting than was mute swan or coot. One or two mobile shooti ng punts reduced wigeon numbers, whereas numbers were unaffected by th e presence of up to 4-6 stationary punts; fishing boats had no effect on wigeon abundance. 5. Hunting, especially shooting from mobile punts , was identified as the most disturbing human activity in relation to staging waterfowl in this area. Similar results and conclusions were r eached in another comparable study area. The results have implications for refuge designs and zoning of disturbing recreational activities.