Although group foragers have the potential to enhance their patch choice decisions by observing the sampling behaviour of competitors (i.e. using 'public information'), empirical support for such an ability is sparse and conflicting. We examined whether wild blackbirds, Turdus merula, were more likely to choose the richer (20-fold) of two seminatural food patches if they had seen other blackbirds (demonstrators) feeding in them beforehand. There was no evidence that birds having such preharvest public information preferentially selected the richer patch, even if their choice was not limited by the continuing presence of dominant demonstrators. Nor did patch selectors favour the patch occupied by a demonstrator (or just vacated by one) despite an above-average probability that these patches were the richer. Instead, our birds often showed preferences for one or other of the otherwise identical patch locations, were more likely to select the rich patch if it had not changed location since their last visit, and avoided dominant conspecifics. We conclude that preharvest public information has little or no influence on blackbird patch choice decisions. (C) 2001 The Association for the Study of Animal Behaviour.
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