Ocean Watch

Monday, May 18, 1998

Golden plover males back
in same spot every year

For those of us who share our yards and parks with Pacific golden plovers, or kolea, each winter, May can be a lonely month.

Our migratory bird friends, each of which spends the winter at the same spot each year, have flown the coop and won't be back till August.

Oh, I know they have to go. Come spring, these shorebirds must head north, where insect-food is abundant, to find a mate and raise their chicks.

Still, at this time of year, I always miss the plovers' distinct call and graceful step, and wonder how they're doing.

I'm not the only one who wonders what, exactly, Hawaii's plovers do in the summertime.

A team of researchers, led by Oscar "Wally" Johnson and funded by the National Geographic Society, have been traveling to Nome, Alaska, since 1988 to study these remarkable birds.

Over the years, the researchers have learned that males return to the same spot year after year, regardless of whether that area is still snow-covered.

Once there, those males defend their territory with all the pluckiness they show in their winter space here in Hawaii.

Females, however, aren't so faithful to a summer nesting site, preferring instead to shop around. Each year, female plovers choose a new mate, perhaps judging a male's suitability by his territory.

Once she's committed herself, both she and the male are monogamous for the season, sharing the household chores of egg sitting and chick tending.

We can thank Johnson, a Montana State University biology professor, for these and countless other facts we now know about our popular kolea.

Johnson and his colleagues have been studying Hawaii's plovers since 1979, the year he took a sabbatical at UH.

With the help of his wife, Pat, and Phil Bruner from BYU-Hawaii, studies have been ongoing ever since.

The team banded one male bird, No. 63, in 1982 at Bellows Air Force Station, and that bird is still making the round trip each year. Since No. 63 was at least 1 year, 9 months old at the time of banding (determined by its adult wing feathers), that makes it 18 years or older this summer.

Two other banded birds will turn 17 this summer.

The maximum life span of Pacific golden plovers is unknown but, from what we know now, probably exceeds 20 years. Surprisingly, the average longevity of these birds is only around 4 to 5 years.

By human standards, life for the average plover seems hard. Each year, in late April and early May, Hawaii's plovers take off for Alaska. These migrations are nonstop and last for several days, an astounding feat for a bird weighing not much more than one-third of a pound.

After the male stakes out his territory and the female chooses a mate, the male makes a shallow, bowl-shape nest adorned with lichens. By early to mid-June, the female has typically laid four eggs in the nest, a tremendous accomplishment since the combined weight of those eggs equals her own.

The birds take turns incubating the eggs, and after 25 days or so, they hatch. The very next day, the downy chicks leave the nest and begin foraging on their own. Both parents work like crazy leading their offspring about in search of insects and, in between, sitting on the chicks to keep them warm.

In August, when the youngsters are only about a month old, the parents take off for Hawaii. Surviving chicks leave Alaska in October or November.

With Wally Johnson's help, I have a much better picture of our koleas' family life during the summer. Still, I look forward to their return in August. The place just isn't the same without them.