This bird spends ten months a year without ever touching down

Common swifts leave their nests in August and don't land again until the next breeding season, eating, sleeping and even mating entirely on the wing. Tracking devices showed some individuals stayed airborne for around 10 months straight, landing less than 1% of the time.

— Anders Hedenstrom et al., Annual 10-Month Aerial Life Phase in the Common Swift Apus apus — Current Biology, 2016