Several functions have been hypothesized for sleep, such as energy conservation and clearance of free radicals. In our study published in Integrative Organismal Biology, we investigated the relationship between sleep behavior, food intake and two markers of physiological condition – the amount of energy reserves and oxidative status – in two migratory songbird species, the Garden Warbler and the Whitethroat.
Although sleep posture preference resulted to be a common energy saving strategy, our results suggests that different species might use different strategies to manage their energy during stopover. In addition, it raises the possibility that migrants have evolved physiological adaptations to deal with oxidative damage produced during migration.
If you want to learn more about this study, you can access the paper by following this link.