Dominance affects resource partitioning in pigeons, but pair bonds do not

Abstract

Pigeons (Columba livia) show individual feeding specializations both in the field and in captivity. In competitive feeding conditions, these specializations change in a way that decreases dietary overlap between birds. We examine two potential status determinants of feeding competition, dominance and pair bonds. In pigeons, pair bonds are used in aggressive feeding coalitions at defendable patches, while dominance affects both feeding rate and priority of access to food. We compared the seed choices of pigeons feeding alone and in competitive conditions with those of a conspecific. In experiment 1, the competitor was either the mate or a familiar nonmate of the opposite sex; in experiment 2, the dominance rank of the competitors was known from a round-robin series of dyadic encounters in the presence of a defendable feeder. Pair bonds had no effect on competitive diet shifts, but dominance did: in competition, lower ranking pigeons ate less of the seed type they specialized on when feeding alone, while higher ranking pigeons ate more. Confirming previous results on resource partitioning, food choice showed less overlap between individuals in competition than in solitary feeding trials, but the magnitude of the change was not proportional to initial overlap.