Which bird migrates the farthest?

The bird that flies farthest is the Arctic tern, an elegant white seabird. This bird also sees more daylight than any other.

Arctic tern in flight

The Arctic tern breeds on the shores of the Arctic Ocean in the Northern Hemisphere summer. And it feeds over the oceans of the Southern Hemisphere half a year later – in Southern Hemisphere summer. So, like many birds, this bird flies great distances every year to maintain its life of endless summertime.

North American Arctic terns fly about 40,000 km each year. That’s a distance about equal to the distance around the Earth.

Two Arctic terns

An Arctic tern can live for 25 years, so in its life-long quest for summer it can fly a million kilometres – nearly three times the distance from the Earth to the moon.

Source - EarthSky.org