Wing Tips: Arctic Terns prepare for 12,000-mile journey north

Somewhere on an island off the coast of Antarctica, an Arctic Tern is preparing to head north, completing the longest round-trip journey known of any animal. This epic flight is known as migration, and although many animals migrate, certain birds are the distance champions.

Our Arctic Tern began his southbound voyage of 12,000 or more miles in the far northern reaches of North America, Europe or Asia, nesting as far north as the Arctic coast. In September, as the sunlight begins to wane in the northern hemisphere, the Arctic Tern heads south in a meandering route away from land until he reaches the islands and mainland of Antarctica. Here he will spend the northern winter in the relative warmth and summer sunlight of the southern hemisphere. Then in March, when daylight wanes in the south, he will retrace his steps to his northern nesting grounds. Along with the longest known annual migration of any bird, the Arctic Tern probably sees more daylight than any other.

In an interesting aside, the closely related and nearly identical Antarctic Tern nests in the far south, but does not travel to the far north for its winter, only as far as South America or Africa.

Although the Arctic Tern has a very long migration, it is by no means the only remarkable one.

The Bar-tailed Godwit is a large shorebird that nests in Alaska. To escape the winter, it migrates south to New Zealand. Instead of following coastlines and making a casual flight with rest stops, it eats until over half of its body weight is stored fat for a nonstop flight to the south. Radio tagged birds have been tracked flying more than 6,000 miles in nine days. Birds are able to undertake these epic journeys by sleeping in flight. Long-distance migrants can rest their brain one hemisphere at a time, giving each side a short rest. In addition, they take very short micro naps of only a few seconds. During the winter, the Bar-tailed Godwit will feed and replenish its fat reserves, only to repeat this migration in the spring. They will be back to nest again in Alaska by early May.

Migration can also provide impressive flocks of birds, and here in Alaska we can view them in several locations. In Cordova, up to 5 million shorebirds visit the beaches to rest and refuel on the rich mudflats on their way to nesting grounds in Alaska. The most common is the Western Sandpiper, but tens of thousands of Dunlin, Semi-palmated Sandpipers, Sanderlings and Whimbrels also join in the feeding frenzy. They will stay for a few days before scattering throughout the state to breed. The Copper River Delta Shorebird Festival in early May celebrates this annual spectacle.

In mid-May, Homer hosts the Kachemak Bay Shorebird Festival, another event dedicated to the annual migration of millions of shorebirds. Both towns have speakers, programs and guided bird watching tours during the festivals.

Hawks, falcons and Golden Eagles that migrate to the Lower 48 for the winter are also beginning their northbound journey, most arriving around mid-April. These large birds need to use prevailing winds to assist them in long flights. Hawks and eagles are designed for soaring rather than for long periods of flapping flight, so they follow mountain ranges with their upwellings of warm air to help keep them aloft. Hawks will often spend a few days in one location along their migration route to feed and wait for favorable weather. Theirs is a long but more relaxed flight.

Here in Southcentral Alaska, the hawks present a bird watching spectacle as they move up the Copper River, through the Mat-Su Valley and on into the Interior. Commonly seen are Harlan’s Red-tailed Hawks, Rough-legged Hawks, Golden Eagles, Sharp-shinned Hawks and swans. In mid-April, the Anchorage Audubon and Mat-Su Birders host a weekend Hawk Watch at about Mile 118 on the Glenn Highway east of Palmer. Join them this year April 14-15, and on the 15th there will be a barbecue grill and potluck picnic. See their websites at matsubirders.org or anchorageaudubon.org.

Nancy Wade is member of the Mat-Su Birders and Alaska WildBird Rehabilitation Center. Send birding questions for her column on birding to alaskaflamingo@yahoo.com.