Daytime sleeping behavior observed in a Black-and-white Warbler during spring stopover

Abstract Nocturnally migrating birds experience loss of sleep during the migratory period especially when undertaking long, non-stop flights. We report a field observation of daytime sleeping behavior in a Black-andwhite Warbler (Mniotilta varia) during spring migration. It is likely that this individual was compensating from sleep loss experienced during a trans-Gulf of Mexico flight. Only a few observations of daytime sleeping behavior have been reported in free-living migrants and all have been associated with long-distance flights in relation to ecological barriers.