Figure 5. Predawn anticipatory crowing does not entrain to a timed crowing sound stimulus under the dimLL condition.

Crowing sound stimulus of familiar roosters was given for 3 hours each day (dark gray shade). Although sound stimulus–induced crowing was observed immediately after the onset of the sound stimulus (arrowhead), anticipatory predawn crowing continued to free-run under the dimLL condition. Data from 1 individual from one of 3 rooster groups.