On The Track To New Technology Monitor Sends Signals From Birds To Satellites

Jim Watson stood on a steep bank overlooking the Skagit River, a bald eagle cradled snugly in his arms.

The unhappy bird struggled and twisted her white head from side to side, opening and closing her beak in mute panic. Taking care to point her wicked yellow talons away from his body, the state Department of Fish and Wildlife biologist leaned forward and flung the eagle into the air.

Flapping her wings ponderously, the big bird barely cleared the leafless willows and cottonwoods lining the river bank, then glided into the forest beyond.

Scarcely visible on her back was a rectangular box a little bigger than a Bic lighter - a powerful transmitter that will send radio signals to a satellite thousands of miles above the Earth. The three-ounce device will allow Watson to track the bird wherever she wanders.

It’s the technological cutting edge in the study of migratory birds and the culmination of two decades of development.

“These little weenie things,” as co-developer William Seegar calls them, have revolutionized researchers’ ability to find out where falcons, eagles and hawks go when they vanish over the horizon on their mysterious, seasonal passages.

“The technology is like a crystal ball that allows us to look into the most remote regions on the surface of the Earth and see things that we could only have imagined until now,” said Seegar, a research scientist for the Defense Department in Maryland. “It sets you free to track animals where, literally, you could never go.”

Without leaving his home office in the North Cascades town of Concrete, Watson has “watched” the eagle he trapped last month make her way to the Nooksack River, near the Canadian border. A few days later, she paused at Pitt Lake, just east of Vancouver, B.C. Next stop was Fitz Hugh Sound, 300 miles to the north, along British Columbia’s wild central coast.

“She’s definitely heading north - possibly up to Alaska,” he said.

The other eight eagles Watson strapped transmitters to this winter on the Skagit have scattered - some heading northeast to interior British Columbia, some moving south to the Yakima River, others heading toward Alaska.

“I’m not sure they’re at their stopping points yet,” Watson said.

The only scientist using satellites to track birds from Washington, Watson hopes to figure out where the hundreds of bald eagles that congregate on the Skagit River each winter come from.

The answer is of more than academic interest.

Steelhead fishermen and federal regulators have tangled over access to the river. The regulators have suggested restrictions on anglers and boaters to reduce disturbance of the eagles, which are a threatened species.

If Watson’s studies show that the eagles come from booming populations, the restrictions may not be needed. But if they come from places where the species is on the edge, it may be more important to ensure that the animals aren’t hassled during their stay on the Skagit.

So far, Watson had been surprised at the diverse origins of the eagles. It also appears that many are unmated birds that stop off for a few days or weeks, then move on.

“Maybe this is a sink for non-breeding adult eagles,” Watson said.

It’s the kind of insight that would have been very tough to glean without satellite telemetry, as the tracking technique is called. The method’s power lies in the bird’s-eye view of the Earth only a satellite can offer.

“If the satellite is over St. Louis, it can see the whole of the United States and most of Canada and Mexico as well,” said Paul Howey, founder of Microwave Telemetry Inc., the Maryland company that produces the transmitters. “It doesn’t matter where the bird goes. We can pick it up.”

The system relies on two weather satellites orbiting the planet’s poles. The transmitters on Watson’s eagles send out regular radio beeps that the satellites pick up as they pass overhead. The satellite sends the data to a ground station, where a computer program pinpoints the bird’s location and passes the data on to the biologist.

“It can happen virtually instantaneously,” Howey said.

Trapping the birds is still a time-consuming job, however.

Watson arrives at the river before daylight to arrange his snare: a tempting steelhead surrounded by a lasso of fishing line he can remotely trigger to cinch around an eagle’s feet.

He waits in his pickup - usually for hours - until a bird takes the bait. Then it’s a mad dash through mud, brush and icy water to reach the frantic bird before it slips the noose.