The arctic tern flies from the frozen arctic at the top of the world to the frozen seas around Antarctica, then returns, every year. It takes a winding course, and so travels more than 40,000 miles each year. The average bird will travel nearly 3 million miles over the course of it's life. That's the equivalent of flying to the moon and back five times.
Least Tern with chick. Terns are birds that are normally found near the sea, rivers or wetlands & typically breed in noisy colonies and lay their eggs on bare ground with little or no nest material. However, the marsh terns construct floating nests from the vegetation in their wetland habitats, and a few species build simple nests in trees, on cliffs or in crevices. The sexes are identical in appearance, but young birds are readily distinguishable from adults.