Posted: November 10, 2004, 12:00 a.m. PDT
Migrating songbirds have chronic sleep deprivation because they fly most of the night and feed all day to rebuild energy reserves, new data shows. Tests suggest, however, that sleep-deprived birds do not show signs of declines in mental abilities.
According to ongoing studies, migrating songbirds only sleep about one-third as much as during nonmigration periods.
Neils Rattenborg of the University of Wisconsin says the discovery of no-cost sleep deprivation in migrating songbirds is "unprecedented.”
The matter of sleep during avian migration has not been studied much and remains an enigma, scientists admit. Some songbirds migrate more than 4,000 miles between breeding and wintering grounds, and they accomplish that feat without any "power napping” during the day.
Laboratory tests using brain sensors show that mental activity is not diminished despite migratory sleep deprivation. Previously, it had been thought that sleep-deprived birds would have impaired learning capacities, but studies suggest that is not the case and that sleep and learning in birds might not be so closely interdependent, according to Jerome Siegel of the University of California Los Angeles.—Robert Alison