Daytime naps in night-migrating birds: behavioural adaptation to seasonal sleep deprivation in the Swainson's thrush, Catharus ustulatus
Author(s):
T. Fuchs*, A. Haney*, T.J. Jechura†, F.R. Moore‡ & V.P. Bingman*
*J. P. Scott Center for Neuroscience Mind and Behavior and Department of Psychology, Bowling Green State University, U.S.A.
†Albion College, Albion, Michigan, U.S.A.
‡University of Southern Mississippi, Hattiesburg, Mississippi, U.S.A.
Many species of typically diurnal songbirds experience dramatic sleep loss during the migratory seasons because of their nocturnal flights. However, nocturnally migrating songbirds continue to function normally with no observable effect of sleep loss on their behavior. Studying the Swainson’s thrush (
Catharus ustulatus), a long-distance trans-gulf migrant, we investigated how nocturnal migrant birds might compensate for sleep loss. We found that in contrast to the non-migratory season, migrating Swainson’s thrushes engage in numerous, brief “daytime naps”, closing either one or both eyes for several seconds. Short “micro naps” may enable migratory birds to compensate for extended periods of nocturnal sleep loss without substantially compromising necessary daytime activities. Because unilateral eye closure in birds is a reliable indicator of unihemispheric sleep, our findings raise the intriguing possibility that nocturnal migrants may in part compensate for nocturnal sleep loss by taking lateralized naps during the day.
DOI (Digital Object Identifier, will open in another window)::
doi:10.1016/j.anbehav.2006.03.008
