An alpine swift can fly non-stop for more than six months straight

GPS-tagged alpine swifts tracked in 2013 stayed continuously airborne for over 200 days during their non-breeding season, apparently feeding and even sleeping in flight. It's the longest uninterrupted flight ever recorded in any bird, overturning the assumption that migratory birds need regular rest stops.

— Felix Liechti, Willem Witvliet, Roger Weber, Erich Bächler, First evidence of a 200-day non-stop flight in a bird — Nature Communications, 2013