Don't let the size of the Arctic tern fool you as to what it can do. This tiny seabird traveled the equivalent of flying twice around the planet in the longest migration trip ever recorded.
The Arctic tern, which weighs about 100 grams (0.22 pound), clocked in 59,650 miles during its migration trip to Antarctica and back. The total distance this tiny seabird traveled is more than twice the planet's circumference.
Last July, the Arctic tern flew from its breeding grounds and started the journey down Africa's west coast. The seabird rounded Cape of Good Hope in South Africa and flew towards the Indian Ocean. In November, the bird finally arrived in Antarctica.
The bird's journey was monitored by a small device attached to its leg. The 0.7-gram lightweight device is believed to have no effects on the bird's flight. In the course of travel, the terns dip down into the sea waters to catch fish to eat during their journey.
"It's really quite humbling to see these tiny birds return when you consider the huge distances they've had to travel and how they've battled to survive," said Richard Bevan, a member of the team who tracked the birds' progress at Newcastle University.
While the Arctic tern is able to complete the longest migration ever recorded, the bar-tailed godwit, another migratory bird, is able to complete the journey from the Arctic to New Zealand in only eight days nonstop. This other migratory bird is capable of completing its migration even without food stops in between.
While the Arctic terns are not endangered species, their populations are believed to be decreasing in recent years. There are over 2,000 breeding pairs of Arctic terns on Farne Islands but the breeding colonies in the Outer Hebrides and Shetlands in Scotland have shown lower numbers of chicks produced.
Experts theorized that this could be the result of climate change as the warm ocean waters cause the sand eels to move towards the north. The breeding colonies of Arctic terns feed on sand eels. Bevan added that the terns are highly sensitive to marine environment changes.
In the study, scientists tagged 29 birds with the leg devices. To date, 20 birds have returned. Some of the birds may have already died during the trip or some of the terns do not fly back to the United Kingdom every year to breed.
Data gathered from the bird trackers need to be further analyzed to come up with a more detailed understanding of these seabirds' migration practices. Furthermore, the data can help determine how climate change can affect the birds' migration routes.
Photo: Bryan Wilkins | Flickr
