By Jan TenBruggencate
Advertiser Columnist

The kolea, or Pacific golden plover, are back from their annual mating sojourn in Alaska.

The birds started returning to the Islands the first week of August, after leaving here during late April.

The first to return each year are the adults, who have left their maturing chicks in the nests on the tundra. The earliest adults were seen about Aug. 1.

The chicks will arrive in late September, said Phil Bruner, a kolea researcher, BYU-Hawai'i professor and director of the school's museum of natural history.

The kolea is a remarkable animal. The birds make a nonstop flight each spring some 3,000 miles from Hawai'i to Alaska, and return each summer, again nonstop. Some birds may go much farther, since they are seen in the South Pacific islands as well as around Hawai'i, but Bruner said it is not clear whether they take a break along the way on intervening islands.

The birds are capable of flying 60 mph, and "in terms of average speed in sustained level flight, they're probably the fastest bird in the world," he said. Some raptors go faster in dives, but not in level flight, he said.

Bruner, who has been conducting annual research on the Alaskan nesting grounds, said male birds build nest cups and attract females, and both parents then care for the young until it's time to leave. Although it is not unheard of, kolea tend not to be faithful to the same partner year after year.

But most are faithful to their feeding grounds here in the Islands. Many residents can identify the same plover returning year after year to the same patch of lawn, and these territorial birds will chase others away from their spots.

"There are some in the population that wander around, but the vast majority are territorial," Bruner said.

Only in the spring, just before the birds fly north, do they band together and stop being loners. The plovers join large flocks that leave Hawai'i for the northern nesting grounds.

Bruner said it is not clear whether they stay together the whole time during the flight north, or whether they also flock up in Alaska for the departure for winter grounds in the Islands.

"Ultimately, they probably break up, since even a small difference in flying speed would quickly separate them," he said. Some clearly arrive alone, but Bruner said he has seen a flock of several hundred birds arrive at once. He believes that is an uncommon event.

Since the chicks are left to their own navigation skills for the flight south, researchers believe many probably are lost at sea. But nobody knows for sure how many.

"I'm sure there's quite a bit of loss," Bruner said.

Jan TenBruggencate is The Advertiser's Kaua'i bureau chief and its science and environment writer. Contact him at (808) 245-3074 or e-mail jant@honoluluadvertiser.com.