Local movements and population density of Water RailsRallus aquaticusin a small inland reedbed

Abstract

The elusive behaviour and preference for dense aquatic vegetation has resulted in a lack of information regarding most aspects of Water Rail Rallus aquaticus ecology. This paper reports on the results of a study of Water Rails within a small (0.5 ha) inland reedbed at Newbridge-on-Wye, mid-Wales, during autumn and winter 1993–94. Birds used a substantial proportion of the reedbed (captures made 30–¸60 m apart), occupying home ranges which appeared to overlap, although different individuals nevertheless favoured different areas of the reedbed. Evidence is presented that the site was deserted during a period of freezing weather, but that birds re-occupied their original home ranges upon their return. Frequent trapping of birds also permitted an estimation of absolute population density (14 birds per ha), a figure much higher than previously recorded at other sites where birds were counted only indirectly. These data indicate that trapping can yield valuable information on aspects of the ecology of this little-known species