One bird flies the equivalent of three round trips to the Moon in its lifetime

The Arctic tern breeds in the Arctic and winters in Antarctica, an annual round trip of roughly 70,900 km, the longest migration of any animal, confirmed by tracking devices in a 2010 study. Because it can live 30 years or more, a single tern can rack up over 2 million km of flight in its lifetime, chasing summer at both ends of the planet.

— Carsten Egevang et al., Tracking of Arctic terns Sterna paradisaea reveals longest animal migration — Proceedings of the National Academy of Sciences, 2010