CAUSAL FACTORS CONTROLLING DUSTBATHING IN BURMESE RED JUNGLEFOWL - SOME RESULTS AND A MODEL

Three-week-old Burmese red junglefowl, chicks Gallus gallus spadiceus, were kept on a 12:12 h light:dark cycle and were observed for 5 days during the light period using a time-lapse video-recorder. Additional light from a 50-W bulb over the cage was provided for 1 h per day either in the morning, at noon, or in the afternoon. Duration and frequency of bouts of dustbathing were recorded. Both measures of dustbathing increased markedly during the time the light/heat stimulus was presented compared with a control group with no extra light. None the less, the absolute time spent dustbathing per day was unaffected by the stimulus: dustbathing was redistributed. The amount of dustbathing during the critical hour did not change from day to day, and returned to control levels immediately when the stimulus was no longer presented, which suggests that the light/heat stimulus had a direct motivational effect. Based on these results and other results in the literature, a causal model of dustbathing is proposed that depends on a Lorenzian process (internal factor) gated by a circadian threshold. The light/heat stimulus alters the threshold, but does not affect the internal factor. Copyright © 1993 The Association for the Study of Animal Behaviour.