Researchers to track Va. falcons

Solar-powered device signals birds' locations to weather satellites

September 15, 2002|By Diane Tennant | Diane Tennant,THE VIRGINIAN-PILOT

COBB ISLAND, Va. - "Falcon just landed in the tower!" Shawn Padgett shouted over his shoulder, as the boat moved in.

The female peregrine stretched her wings and sidled two steps before launching into the air with a screeching protest against his arrival. With 4 miles of open water between the Eastern Shore and Cobb Island's fiddler crabs, deer and jackrabbits, the isolated spot had been a perfect nesting site. Now these guys had arrived.

The smaller male bird circled the nest, alternately gliding on thermal currents and flapping into the wind.

`The chick's there'

"The chick's there," Padgett said. "They wouldn't be wasting their time in this heat if it wasn't."

A falcon specialist at the College of William and Mary's Center for Conservation Biology, Padgett was hunting the chick, a male soon able to fly, to harness a miniature transmitter to its back. The solar-powered device will signal weather satellites in polar orbit, allowing Padgett - and Internet users - to track the bird's movements.

The center hopes to attach 18 such transmitters this year to young peregrines, just before they leave their nests. Researchers will gain insight into how far the birds travel, whether they migrate and where they nest.

"This chick is about 36 days old," said Mitchell Byrd, director emeritus of the center. "We're hopeful it doesn't fly. Normally, the males fly at 42 days of age, but a single chick like this, sometimes their development's a little bit more precocious."

The men prepared to slog a short distance through the marsh to reach the nesting tower, built in 1980 as scientists reintroduced peregrines to Virginia. Peregrines were nearly extinct in Virginia then, decimated by the pesticide DDT, which thinned their eggshells to the point of breaking. None had bred in the state since the early 1960s.

Padgett climbed a tower to reach the falcons' nest.

25 chicks

Peregrines nested on the tower within a year, and the population has made a slow, steady recovery, to the point that 17 nesting pairs were known in Virginia last year. The birds were removed from the federal endangered species list in 1999, but Virginia still considers them threatened.

Cobb Island has produced about 25 chicks. In May, when Padgett endured the parents' wrath to examine the nest protected by an igloo-shaped doghouse, he found one egg hatched, one in the process of hatching and two others. Only one chick survived. He scaled the tower for it.

He reached into the nest and grasped the youngster, which promptly added its rapid-fire kee kee kee to the screams of the parents. White, downy feathers floated away on the wind.

"Another couple days and this bird would have been out of the nest and ready to jump," observed Bryan Watts, director of the center. That propensity for jumping off heights has led to calamity at several peregrine nests on bridges in Hampton Roads. While the babies are ready to fly, they cannot swim, so researchers have taken many chicks from dangerous nests and fostered them out to birds in the Shenandoah Valley, the traditional haunts of the carnivorous falcons.

One bird released there last summer has already surprised scientists. The tiny transmitter on its back has shown that it moved to Baltimore, ventured several times into New York City, visited Maine, Ohio and Lake Ontario, then flew back to Baltimore. "We had no idea they made movements like that," Byrd said. "Two hundred miles in a day. Peregrinus means `the wanderer,' so they're aptly named."

Within 150 yards

The Cobb Island birds, however, were not traveling far from their screaming baby. Tucked into a mauve pet carrier, the chick calmed down while it was lowered on a rope, then carried to a dry spot on shore.

While Watts held the chick, Padgett fastened the transmitter to a backpack-style harness made of neoprene and polyester, strapping it across the bird's chest and onto its back.

A receiver tuned to the right frequency beeped like a computer modem connecting on a phone line.

As four satellites made passes in turn - about 10 minutes from horizon to horizon - the transmitter signaled. Four signals in one pass will allow researchers to pinpoint the birds' locations to within 150 yards.

"This is very exciting," Byrd said. "It will, for the first time, give us information on where they go immediately from fledging," or growing the feathers necessary to fly.

Padgett finished riveting the harness together, a quicker process than when harnesses were stitched together with dental floss. Watts released one wing from his grip to ensure the feathers weren't snagging anywhere.

"This bird is going to be named Baker," Padgett said, for the late Paul Baker, an aeronautical engineer who designed the Corsair airplane and who happened to be Byrd's neighbor and a supporter of the Center for Conservation Biology.

The public will be able to go to the center's Web site and follow the prompts to Baker's picture. Clicking on his picture will pop up a map showing the bird's location.

Padgett and Watts scaled the tower again and crouched on the edge of the platform to pour bottled water all over the chick. A wet bird, they explained, is less likely to fly or jump off the platform after release.

The adult pair circled above and screamed defiance as Padgett stuffed their baby back into the igloo. He pulled a tick off his knee and climbed down. "Whoo-oo," he exclaimed.

"All right!" Watts agreed, and looked back up. "Well, that was successful."

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