Observation of daytime sleep-like behavior in a migratory songbird during stopover

Abstract

Nocturnal migration is accompanied by sleep loss likely dependent upon the length of the migratory flight. Migrants may minimize the effect of sleep deficit by inserting brief naps into their daytime activities. On 25 April 2006, I observed daytime sleep-like behavior by a radio-marked male Hooded Warbler (Wilsonia citrina) at a coastal stopover site in southwestern Louisiana. The bird likely completed a flight across the Gulf of Mexico a few hours before the observation and departed from the stopover site the evening of the day of arrival. To my knowledge, this is the first reported field observation of daytime sleep behavior in a neotropical landbird migrant. The behavior exhibited in the field was consistent with behavioral characteristics of daytime sleep observed in captive migrants. © 2009 The Wilson Ornithological Society.