Zebra finches in poor condition produce more and consume more food in a producer-scrounger game.
Résumé
When they forage in groups, animals can search for their own food (producer tactic) or exploit the discoveries of others (scrounger tactic). Previous experimental inquiries have demonstrated that individuals vary in their tendency to play either tactic but the extent to which individual factors influence variation in foraging behavior are little studied. In the present study, we have assessed the influence of natural variation in body condition on the differential use of social foraging tactics and their resulting payoffs in zebra finches (Taeniopygia guttata). The producer tactic was found to yield more consistent and predictable rewards across trials than the scrounger tactic. The use of producer was related to reduced variation in food intake and an increased amount of food consumed. We found that poor-condition birds were more likely to produce and so consumed more seeds than good-condition birds. The results are consistent with theoretical models of variance-sensitive social foraging but suggest that scrounging may not represent a variance-averse option in all situations. We propose that in a producer-scrounger context, the variance-averse option may depend on group size and food clumping. Finally, we discuss our results in relation to interindividual differences in metabolism and behavior.