Moonlight controls when the red-necked nightjar eats, migrates and raises young, according to the study. The migratory bird, which breeds in southern Europe and winters in West Africa, follows the lunar cycle.
During a full moon, the bird can hunt insects almost all night long. Nesting is also controlled by the rhythm of the moon – eggs are laid so that the young hatch when the availability of nocturnal insects is greatest.
When the nights are dark, it is forced to hunt briefly at dusk and dawn. The bird also saves energy by slowing down and lowering its body temperature.
"Unlike bats, the nightjar lacks the ability to navigate effectively in total darkness. This is an animal that lives on the margins. Without moonlight, the energy budget simply doesn't add up," says Anders Hedenström, professor of biology at Lund University, in a press release.
The study is based on ten years of fieldwork in Doñana National Park in Spain, and has been published in the journal Science Advances. The birds were monitored with multisensor data loggers developed at Lund University.
