The Arctic Tern Migration: A Most Amazing Journey
Animals all over the planet migrate, from the tiny butterfly to the great whale. However, no other animal migration can compare to that of the Arctic Tern.
The Arctic Tern is a type of seabird. They can be found in places around the world; some of which consider them to be a threatened species. They feed on smaller marine animals and can have a particularly long life for a bird—20 to 30 years is not uncommon. Oh, and they migrate an average of 44,000 miles (70,900 km) per year.
Arctic Terns follow a rather interesting flight path from their breeding grounds to their migratory homes. Scientists discovered this path by using a geolocator to track their migration. Geolocators record light intensity and this is used to generate geographical positions each day. The study—conducted by researchers from BAS, Denmark, Greenland, Iceland, and the US—was published in the journal Proceedings of the National Academy of Sciences.
The Arctic Tern starts their migration from breeding grounds in Greenland. Their first layover on this massive flight of theirs is in the North Atlantic Ocean—for at least a month. Researchers are guessing that this extended break is used as a chance for the birds to fill up on food before continuing to the rather barren waters of the south.
Once they take flight again, they’ll make their way down the coast of northwest Africa and one very interesting thing happens along this portion of the route. When the Arctic Terns reach the Cape Verde Islands, half of them will continue down the coast of Africa and the other half will go back across the Atlantic Ocean and follow a parallel route along the east coast of South America.
Once they reach their final destination—the Weddell Sea near the shores of Antarctica—they will spend our winter months there (or the Antarctic’s summer). When it’s time to come back home, their route back to Greenland is no less strange than the one leaving it. Basically, their return route is like a zigzag or giant S path, which includes a detour of several thousand miles (km) they could avoid if they took a more direct route. However, this seemingly out-of-the-way route is actually to their benefit. By following it, they are taking advantage of the global wind system and as such, are also reducing the amount of energy they need to use to get back home.
I can’t say I blame them for it. A total lifetime of migrations for one Arctic Tern would equal 3 trips to the Moon and back—that’s a lot of distance to cover! It’s also twice the average migratory distance of a regular Tern. You may also be interested in knowing that 44,000 miles is not the record migration for them—50,700 miles (81,600 km) is.
The next time you may find yourself on an unexpected or unwanted long journey, think of the Arctic Tern migration and I’m sure you’ll start feeling better in no time.
By Heidi Marshall