Observation of Daytime Sleep-like Behavior in a Migratory Songbird during Stopover

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

“…Migratory birds may compensate for loss of sleep by engaging in short bouts of daytime sleep [5][6], and our observation of a male Black-and-white Warbler behaviorally asleep for 159 seconds as well at that by Nemeth [7] are consistent with that mechanism. Further, Fuchs et al [5] indicate that episodes of daytime sleep in migrants may typically last around 9 seconds and range up to 2-3 minutes.…”

“…Both our observation and that of Nemeth [7] took place along the northern Gulf of Mexico coast on migrants who are presumed to have completed a long, non-stop flight just hours before. Schwilch et al [22] in a study with songbirds having just completed a 14-16 hour flight which included crossing the Mediterranean Sea also reports sleep-like observations when birds were placed and observed in cages.…”

“…We also noted at least two other migrants foraging within 1 meter of our observed individual. As suggested by Nemeth [7] who reports a similar observation, migrants may be able to utilize cues and alarm calls of other birds while engaging in behaviors that would otherwise leave them vulnerable.…”

“…Observations of migrants shortly after migratory flights are likely to be revealing since compensatory sleep may necessary following prolonged, strenuous flights (e.g., long flights across ecological barriers). Nemeth [7] reported an observation of daytime sleeping behavior in a Hooded Warbler (Setophaga citrina) shortly after the individual crossed the Gulf of Mexico, at the same research site as the current report. However, the majority of published observations of daytime sleeping behavior have been in captive studies and questions remain as to how frequently this behavior is utilized in songbirds on stopover.…”

Circadian control of nocturnal songbird migration

“…Despite being adversely affected by sleep loss during the non-migratory season, nocturnal migrants can obviously reduce sleep for longer periods without associated deficits in cognitive abilities (Rattenborg et al 2004). Sleep-loss during nocturnal migration could be compensated through "micro-napping" during the day (Fuchs et al 2006, Fuchs et al 2009, Németh 2009, Jones et al 2010. However, whether the expression of Zugunruhe represents a disruption of the neural system controlling diurnal sleep-wake cycles is currently uncertain.…”