A test of cues affecting habitat selection by wading birds

We examined foraging-habitat selection by free-ranging wading birds presented with different social and environmental cues by conducting two experiments in eight replicate ponds adjacent to the northern border of the Florida Everglades. The first experiment examined the relative influence of a social (presence of a flock of decoys) and environmental (water depth) cue on the selection of ponds. The second experiment examined the influence of two environmental cues (water depth and fluctuating water level) on the selection of ponds. In the first experiment, wading birds were most attracted to ponds with both the presence of a flock of decoys and shallow water. The social and environmental cues both had the same attractive potential to wading birds. In the second experiment, birds were again attracted to ponds with shallow water; however, fluctuating water level had no significant influence on foraging-habitat selection. If birds do not perceive fluctuating water levels as a cue to habitat quality, then the well-documented relationship between nesting success and fluctuating water levels likely stems from birds responding to factors that covary with water-level changes.