Working and scrounging by zebra finches in an operant task

Groups of three zebra finches were housed in cages which could be adjoined to an operant chamber. Food was restricted and its availability was signalled by a red light projected behind an operant key (an autoshaping procedure). In addition to the shaping contingency, a single peck to the illuminated key, produced food immediately. Following the first peck to the illuminated key, by any subject in the group, the entire group was placed on a schedule of continuous reinforcement (CRF) wherein hopper operation was contingent upon a keypeck during the light. Comparison of individual's behavior revealed a differential pattern of operant working; one group member worked consistently, one worked periodically and one made few (if any) operant responses. All members consumed some reinforcers. The results suggest that zebra finches, under certain conditions, will form specialized labor roles. These data support similar demonstrations with primates (Chalmeau, R. and Galleau A., 1993. Behav. Processes, 28: 173-180), pigeons (Giraldeau, L. and Lefebvre L., 1987. Anim. Behav., 35: 387-394.) and rats (Thullier, F., Desor, D., Mos, J. and Krafft, B., 1992. Psychol. Behav., 53, 17-20).