BlueGreen Labs is happy to announce the release of our new ornithology research on the foraging behaviour of three swift species during moonlit nights. This work has been released as a pre-print on bioRxiv, and is currently being screened for review. This study is follow up work of our paper in Oikos titled: “The aeroecology of atmospheric convergence zones: the case of pallid swifts”.
Abstract
Recent studies have suggested the presence of moonlight mediated behaviour in avian aerial insectivores, such as swifts. At the same time swift species also show differences in prey (size) preferences. Here, we use the combined analysis of state-of-the-art activity logger data across three swift species, the Common, Pallid and Alpine swifts, to quantify flight height and activity responses to crepuscular and nocturnal light conditions. Our results show a significant response in flight heights to moonlight illuminance for Common and Pallid swifts, while a moonlight driven response is absent in Alpine swifts. Swift flight responses followed the size dependent altitude gradient of their insect prey. We show a weak relationship between night-time illuminance driven responses and twilight ascending behaviour, suggesting a decoupling of both crepuscular and night-time behaviour. We suggest that swifts optimise their flight behaviour to adapt to favourable night-time light conditions, driven by light responsive and size-dependent vertical insect stratification and weather conditions.
Reference
Hufkens et al. Moonlight synchronous flights across three western palearctic swifts mirror size dependent prey preferences. bioRxiv 2023.04.25.538243; doi: https://doi.org/10.1101/2023.04.25.538243.
