Nov 052009
photo courtesy of cheesy42 on Flickr Creative CommonsHomeArctic Circle, Antarctica, Northern North America
Habitatopen ocean, rocky land for nesting
Nichemigratory bird, aerial divebombing predator
Lengthbetween 13 and 14 inches
Weightup to 4 ounces
Annual Migration20,000 miles

The marathoner of the skies is not so remarkable in appearance.  A white bird not much bigger than a crow, the arctic tern is nonetheless a wonder of the skies on earth.

The arctic tern spends much of its life in flight. With a 3 foot wingspan and forked tail for navigating, it is anatomically designed for life in the air. It even feeds from the air, catching insects in flight and plucking fish from the surface of the ocean. It has to feed and fly because for the majority of its existence, it’s got somewhere to be, and can’t stop for long.

The arctic tern ranks at the top when you’re talking about long-distance fliers. Every year, this amazing bird flies 10,000 miles to reach its destination…twice.

Terns undertake this grueling journey each year for two main reasons. One is food. Food is plentiful in the polar summer, regardless of which polar summer that is, north or south. The terns join throngs of other animals looking to capitalize on the rich feeding grounds.

The other reason for the journey has to do with light. Each autumn, the arctic terns fly from the northernmost  latitudes of earth to the southernmost, and they do it in order to make the most of the available daylight all year round for nesting and rearing young. Few creatures of earth see as much daylight in a lifetime than the arctic tern sees.

The amazing journey begins in the north. Giant colonies of arctic terns in the Canadian Arctic, Northern Europe, and Sibera sense that the Arctic summer is coming to a close. Then, like a great global airforce, they converge on a point north of Africa. As the colonies converge, they swing south, hugging the African shoreline until they reach the southern ocean. Powerful winds produced from Antarctica’s bitter cold blow the terns to the east, where they will spend the southern summer. In three months time, when the southern sun begins to dip below the horizon, they will begin the long and treacherous journey back, retracing their 10,000 mile journey.

The oldest recorded arctic tern was 26 years old. That means it flew more than 620,000 miles in its lifetime.

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