Ocean
Watch
Monday, April 26, 1999
Researchers to plumb
ways of the plover
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.
But 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.
