Foraging decisions: prey choice by pigeons

Four pigeons, Columba livia, served as subjects in a foraging analogue testing the predictions, both qualitative and quantitative, of the prey choice model. In experiment 1, the search cost between successive prey encounters was varied. In experiment 2, the proportion of rich to poor prey opportunities was varied. In experiments 3 and 4, both search cost and the proportion of rich to poor opportunities were varied in order to manipulate the encounter rate with only the rich prey type and only the poor prey type, respectively. In every experiment nearly all rich prey type opportunities were accepted when offered. Further, as the encounter rate with the rich prey type decreased, the subjects accepted more poor prey type opportunities (experiments 1-3). Both of these results conformed to the predictions of the prey choice model. The acceptance of the poor prey type often, but not always, approximated the all-or-none selection predicted. Selection of the poor prey type changed when the encounter rate with only the poor prey type was varied (experiment 4), in clear violation of the predictions of the prey choice model.