Avian research reveals extreme flight and sleep adaptations

Research has highlighted remarkable physiological adaptations in birds that allow for extended periods of flight without landing. Studies on the common swift (Apus apus) conducted by researchers at Lund University in Sweden revealed that these birds can remain airborne for up to ten months during their non-breeding season. Using electronic devices equipped with accelerometers and light sensors, researchers observed aerial activity during more than 99% of this period.

Complementary research on the great frigatebird (Fregata minor) has provided direct evidence of sleep occurring during flight. By using brain activity recorders, scientists observed unihemispheric sleep, a process where one hemisphere of the brain rests while the other remains alert. During studied flights, frigatebirds averaged approximately 42 minutes of sleep per day, often maintaining an open eye connected to the awake hemisphere to monitor their direction while gliding on air currents.