Distribution and Foraging Behaviour of Grey Herons Ardea cinerea in Adjacent Tidal and Non-Tidal Areas

Dirk Draulans, Jan Hannon
1988 Ornis Scandinavica  
J. 1988. Distribution and foraging behaviour of Grey Herons Ardea cinerea in adjacent tidal and non-tidal area. -Ornis Scand. 19: 297-304. Foraging activity and behaviour of Grey Herons were recorded in a tidal and an adjacent non-tidal brackish water area to investigate whether herons behaved differently in the two areas. This was not the case. Distribution of foraging herons and overall fishing success were similar, despite large differences in food availability. Foraging success did not vary
more » ... uccess did not vary much in the course of a day in the non-tidal area, but in the tidal area foraging was much more successful at high tide and almost impossible at low tide. This, however, did not seem to cause a shift of birds from the non-tidal to the tidal area. In neither area did numbers of foraging herons and fishing success vary much in the course of the winter. Weather variables, on the other hand, influenced heron distribution and foraging success, with herons shifting towards the tidal area during windy, rainy and cloudy weather, when foraging became relatively more efficient there. This could indicate that generally both areas are equally profitable to herons, despite large differences in the spatial and temporal availability of prey.
doi:10.2307/3676725 fatcat:j24utz53trem3kpvops4o3l5si