Ocean Watch
By Susan Scott
Monday, April 26, 1999
In most parts of the United States, people know spring has sprung when they feel a balmy breeze, hear birds calling for mates or see shoots pushing up through the ground. Researchers to plumb
ways of the ploverBut we Hawaii residents have our own harbinger of spring: We notice our golden plovers have donned tuxedos.
These migratory shorebirds, called kolea in Hawaiian, fly to Hawaii in late summer and early fall, then return to insect-rich Alaska each April to mate and raise their young. Before they go, however, they molt into breeding plumage. Brilliant black and white feathers mark the birds' fronts and sides; rich golden feathers fleck their backs and wings.
Last week, anyone walking through Hawaii's beach parks or past grassy yards would have noticed the birds' breeding colors were at their peak. This means that sometime this week, most of them will take off.
Where they go exactly, and how long it takes them to get there, has always been a hard-to-solve puzzle for ornithologists. But this year, some advanced technology is helping two plover researchers find the answers to those questions.
Montana State University researchers Oscar "Wally" and Pat Johnson, with Minnesota assistant Ron Kienholz, last week attached tiny radio transmitters to 40 of Hawaii's kolea.
This is easier said than done. The demanding work involves arising at 3 a.m. to set up fine, mesh nets on grassy areas at Bellows Air Force Station. When the plovers start feeding, the people walk near them, causing the birds to fly into the net.
Gently, the workers weigh the birds, place ID bands on their legs and then epoxy a tiny radio transmitter to feathers on each bird's back. The radio transmitters weigh only 1.5 grams, which is less than 1 percent of the bird's weight.
This whole process barely fazes these hardy birds. I watched one male plover get "wired" and was amazed at the bird's docile acceptance of being handled. The plover neither struggled nor snapped, and, when released, it flew only a short distance from us.
Apart from the tiny radio antenna trailing down the bird's back, the plover looked normal. Soon, after fixing a few ruffled feathers, the bird was performing its distinctive stop-and-go search for breakfast.
When the radioed birds take off this week, researchers here will notify Alaska co-workers, who will then fly over plover breeding grounds in two small planes. When the pilots hear a signal, detectable about 15 miles up, they will be able to identify the birds since each transmitter sends a unique frequency.
In this way, researchers will know exactly where the Bellows birds went and approximately how long it took them to get there.
When the birds go through their natural molt in the summer and fall, the radio falls off, and the bird continues its life unharmed.
Perhaps when our plovers begin returning in August, we'll know a little more about their journey.
Marine science writer Susan Scott's Ocean Watch column
appears Mondays in the Star-Bulletin. Contact her at honu@aloha.net.
