Chickadees neither win-shift nor win-stay when foraging

The win-shift versus win-stay distinction supposes that foraging animals use one of two movement rules when searching for food: win-stay to return to locations where they previously found food and win-shift to avoid locations where they previously found food. Win-shift and win-stay rules describe, for example, the behaviour of rats foraging in a radial arm maze, the behaviour of animals in delayed matching and nonmatching to sample tasks, and the behaviour of nectarivorous birds feeding on depleting and replenishing nectar sources. The present study investigated whether black-capped chickadees, Poecile atricapillus, searching for food use win-shift and win-stay rules in response to different reward contingencies. Chickadees first searched multiple spatially dispersed sites for food hidden randomly in these sites, then after several minutes returned to find these sites replenished in the win-stay condition, or empty and other sites baited in the win-shift condition. Birds performed no better than chance at returning to baited sites in the win-stay condition or avoiding previously baited sites in the win-shift condition. Instead, chickadees used preferred search patterns regardless of the win-shift or win-stay contingencies they experienced. Search sequences, however, showed greater stereotypy under win-stay than under win-shift conditions even though the locations of baited sites were determined randomly. Chickadees are year-round residents in relatively small home ranges and may forage using well-established movement rules that, in our experiments, led to neither win-stay nor win-shift behaviour. The stereotypy of search does, however, appear to be influenced by win-stay and win-shift foraging outcomes.