Nocturnal migration of night hunters

Abstract

Ecology Bird migration is a vast global biannual phenomenon requiring food as fuel on a similar scale. Superimposed on these twice-yearly events are other regular occurrences, including tightly predictable lunar cycles. Norevik et al. wondered how the moon might influence migration of birds that hunt at night, such as the European nightjar Caprimulgus europaeus . These birds hunt insect prey by sight and are more active during moonlit nights, giving a monthly boost to their food intake. Using GPS-linked data loggers, the authors found that migration activity in these birds en route tends to peak after a full-moon feeding binge. The lunar cycle strongly synchronizes migration responses among individuals, which means a large proportion of a population migrates simultaneously. Such synchronized responses may make them vulnerable to climate change–related or other adverse events along their migration route. PLOS Biol. 10.1371/journal.pbio.3000456 (2019).