Spying on Falcons From Space

On a narrow aerie 600 feet above the tundra, Thomas Maechtle edges toward the falcon’s nest with four brown wooden eggs tucked under his arm and a monofilament snare looped around his yellow hard hat.

Two enraged peregrine falcons--talons extended--swoop and scream around his head.

Dangling from the cliff face on a safety line, Maechtle is stalking one of nature’s most spectacular birds of prey--a two-pound aerial acrobat that, diving at speeds up to 200 mph, can strike its quarry out of the sky in an explosion of feathers.

If all goes well this day, these falcons will spend the next year under continuous satellite surveillance.

Maechtle, a biologist with Boise State University’s Raptor Research Center, and his colleagues have trekked north of the Arctic Circle in high summer to test a new generation of miniaturized tracking technology that allows a wildlife biologist to shadow an animal anywhere in the world.

The U.S. Department of Defense is funding their work because the Pentagon is under increasing public pressure to defend endangered species as vigorously as it does U.S. citizens.

Controlling nearly 25 million acres of fish and wildlife habitat--equal in size to Kentucky--the Pentagon oversees the homes of 100 federally listed threatened or endangered species. The Defense Department now has natural resource management plans at 218 bases, including some abroad, and hopes to have one in place at every U.S installation by 2000.

Consequently, the Pentagon must learn to co-exist with the wildlife on military posts or drastically curtail its activities to avoid spoiling key breeding areas and feeding grounds; yet many of the animals it is called upon to protect are too leery of humans to be easily monitored by conventional means. The areas they inhabit also may be closed to fieldworkers for reasons of military secrecy or safety.

The answer, some biologists believe, is to harness wildlife to satellite technology.

Once the falcon is snared safely, Maechtle and Marco Restani, from Montana State University in Bozeman, will fit the bird with a tiny transmitter that will connect the falcon to an international satellite network. The satellites, moving in a low polar orbit every 120 minutes, can track the bird’s signal wherever it goes, no matter how far it travels, what kind of weather it encounters or how inaccessible the terrain where it chooses to roost.

Wildlife biologists are using the tiny transmitters to develop fundamental insights about wide-ranging birds and mammals by locating the regions where they winter, the paths they follow in their annual journeys and any environmental threats they may encounter on the way.

“This system serves as a crystal ball that allows you to peer into remote places and hidden behaviors of virtually any creature in the wild,” says William S. Seegar, the U.S. Army scientist who oversees the wildlife tracking project.

Technology of Conservation

In a series of field trials over the last five years, research biologists have used the $2,500 transmitters to track about 500 birds in an effort to answer the conservation questions posed by wide-ranging species.

They have followed endangered bald eagles from the Chesapeake Bay to Alaska, tracked threatened Swainson’s hawks from their roosts in California to the pampas of Argentina, and monitored the global migrations of 20 other species.

To explain why the Pentagon is so eager to adopt the new technology of conservation, Seegar notes that the Orchard Training Area in Boise--the country’s third-largest National Guard training facility--is in the middle of the Snake River Bird of Prey National Conservation Area.

This year, Seegar’s group is tracking the movements of golden eagles and two endangered species of hawks to help base commanders better understand how to conduct their business without damaging the animals or their habitat. Almost anything the military does to maintain its readiness--from shelling target ranges to large-scale maneuvers--is by its nature potentially harmful to wildlife.

The team also is tracking species on other military reservations by satellite: herds of Oryx antelope at the White Sands Missile Range in New Mexico; wild horses and hawks at the Dugway Proving Ground in Utah, and pelicans and white-faced ibis at Naval Air Station Fallon outside Reno.

Now the military has turned its attention to the Arctic falcons, which range across the western hemisphere.

In annual pursuit of the migrating birds on which it feeds, the raptor may fly as far as South America, stopping throughout the United States.

Greenland falcons have been seen as far south as Buenos Aires and at the headwaters of the Amazon. One team tracked 17 peregrines from the Yukon River in Alaska to wintering grounds in Brazil, Mexico, Honduras, Cuba and El Salvador. One bird was followed for nearly 9,000 miles.

By monitoring a single peregrine, the researchers also can keep track of the birds it hunts--flocks of shore birds and migratory waterfowl numbering in the millions--no matter how many national borders they cross.

“We will be able to link their northern breeding grounds to their wintering grounds, with where they stopped on the way and when,” says Seegar, a senior scientist at the U.S. Army Edgewood Research and Development Center in Aberdeen, Md. “You could not get this information any other way.

“We want to develop a transcontinental migration model to assist us in determining what kinds of weather fronts precipitate bird migrations.” By better understanding what guides the movements of such large flocks, military aviators may have a better chance of avoiding them in flight, he says.

As he talks, Seegar is kneeling on the Arctic heath, perfumed with insect repellent and enveloped in a living fog of rapacious Arctic mosquitoes.

Only the nesting falcons give this trackless tundra--bordered to the east by a blue wall of glacial ice and to the south by a river of meltwater braided through bars of sand and grit--any special identity. The aerie is 30 feet from the top of a granite crest that field biologists call Icecap Cliff.

Ignoring the insects as best he can, Seegar keeps his spotting scope trained on the falcons wheeling above the aerie. He reports their movements via radio to the men working on the cliff face.

Despite these advanced tracking techniques, the biologists hanging off the cliff face still must catch their birds by hand.

When the falcon is trapped, they must move quickly--not only to keep from agitating the bird but also to return the four eggs to the warmth of their mother’s nest as quickly as possible. If the eggs are chilled, the unborn chicks may die.

As Seegar watches, Maechtle swiftly exchanges the eggs in the nest for decoys, then sets the snare around the rim of the nest, where he hopes it will trap the female falcon as soon as the furious bird settles back in. The decoys ensure that the real eggs will not be damaged by the struggle.

The falcons, however, are in no mood to cooperate.

“OK, now the moment of truth,” Seegar mutters into his radio.

“The bird is walking into the nest. She’s walking in. . . . Bingo. Screwed. She’s just spinning around and smashing your noose.”

The falcon screams in satisfaction and soars away.

Gingerly, Maechtle and Restani climb back down to the aerie to reset the snare.

1970s Disaster Sparked Curiosity

Through binoculars, William Mattox watches with almost paternal pride as the falcons soar above the men on the cliff.

“The peregrines are spectacular fliers. Pilots and aerobatic fliers have been entranced by the species. The peregrine is a magnetic species.”

An Ohio-based environmental consultant, Mattox has devoted 25 years to tracking and tagging the falcons of Greenland.

In all, he has tagged 1,886 peregrine falcons and identified 124 nesting sites.

The information he has gathered in decades of backpacking expeditions across the tundra has become the basis for the Defense Department’s satellite tagging study by providing the locations of the nesting sites and the basic information about the falcon’s habits.

“There is a huge amount of untapped information here,” he says.

Mattox is not a paid ornithologist; he is a dedicated amateur bird-watcher who has carried out his meticulous field surveys during summer vacations since 1972.

His scientific curiosity about the birds here was triggered by an environmental disaster that by the early 1970s had all but wiped out the peregrine falcons in North America and Europe.

Their precipitous decline was caused by pesticides such as DDT and dieldrin that contained chlorinated hydrocarbons. These pesticides--long since banned in the United States--inhibit an enzyme that reinforces eggshells with calcium, resulting in thin-shelled eggs that break before hatching.

As raptors perched at the top of the food chain, the peregrines are especially vulnerable to any environmental poison. As they devour prey exposed to traces of the chemicals, toxic doses concentrate in their bodies.

The birds became virtually extinct east of the Mississippi River, and in the Western United States, the number of birds dropped to about 300 pairs. But there was no evidence of this plight in their Greenland home until Mattox set out to collect it.

When he began in 1972, all that was known about the falcons of Greenland was what could be gleaned from occasional sightings as the birds paused in their annual migration at Assateague Island off the coast of Virginia or at Padre Island in Texas.

Mattox quickly learned that even the tundra peregrines of Greenland--relatively isolated for much of the year--balanced on the brink of extinction. Not until 1994 did the U.S. Fish and Wildlife Service remove the Arctic falcons from the endangered species list.

Although they no longer worry about DDT, researchers today are concerned that the falcons may fall victim to other chemicals sprayed in the regions where the birds winter. High levels of the toxic industrial chemical PCB, for example, have been detected in three of every four peregrine falcons tested.

The satellite tracking system has already helped researchers determine where other birds may be encountering the toxic chemicals as they migrate, revealing the intimate ties between species in North and South America.

In a pioneering 1994 study, U.S. Forest Service ornithologist Brian Woodbridge, puzzled over an inexplicable decline in Swainson’s hawks, used the satellite technology to track two hawks from the Butte Valley National Grasslands in northern California to the La Pampa province of Argentina.

It was the first time anyone learned where the endangered hawks spend their winter. When scientists subsequently visited the roosting spot, however, they discovered 700 dead hawks in nearby farmers’ fields.

That was enough to trigger a more thorough investigation, and in 1995, researchers tracked 12 Swainson’s hawks as they migrated from Saskatchewan, Idaho, Utah, California and Colorado. When researchers visited the nesting areas pinpointed by the satellite data, they discovered thousands of dead birds in the worst hawk kill ever recorded--all apparently poisoned by eating grasshoppers contaminated with the pesticide that Argentine farmers used for insect control.

The pesticide degrades so quickly that no residues were ever found in the blood or tissues of the hawks that survived to return to North America. Without the satellite tracking system, biologists might never have learned why so many thousands of hawks were vanishing.

The discovery led to a remarkably successful international rescue effort, and the birds appear to be recovering. Nonetheless, this fall, as the hawks begin their 12,400-mile round trip from California to South America, six more birds will carry satellite transmitters.

“The technology really saved that species,” Seegar says.

Concerns Over Harming Birds

On the cliff face, Maechtle and Restani reset the falcon snare. They retreat up the rocks, as a gentle drizzle begins.

Seegar and Mattox train their scopes on the aerie and wait.

“Perched!” says Mattox. “She is caught.”

Avoiding her slashing beak, Restani carefully lifts the falcon from the nest. Maechtle wraps a shawl around her wings then slides it into his fanny pack while he clambers up the cliff. Then Restani replaces the eggs in the nest.

Upon examination, they discover this falcon is no stranger. The information on its leg band shows it was first tagged in 1993, then caught again in 1995.

They loop the transmitter’s Teflon straps around its wings, adjust the fit, and release the falcon.

The biologists acknowledge that their activities agitate the birds, but say that any harm they may do by capturing and tagging them is outweighed by the data they can gather, which may help ensure the survival of the species.

When the group first started tagging the Greenland falcons, the Danish government, which licenses the field research, was concerned the biologists might damage the hatchlings’ chance of survival by handling the eggs.

But a controlled study of several hundred nests persuaded the researchers that they are not harming the birds or their young.

Indeed, several weeks after the falcon at Icecap Cliff was caught and released, four healthy fledglings hatched in the nest. The team bands all four--two males and two females.

In all, the team has mounted transmitters on six peregrine falcons in Greenland.

Now as summer turns into fall, the satellite signals indicate that the first of the peregrines has begun its annual flight south.

This month, Seegar hopes to catch a glimpse of the peregrines from his autumn bird-watching post at Assateague Island in Virginia, while Maechtle will be looking for them at Padre Island where they also often pause in their annual journey.

“They are on the move,” Seegar says.

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Bird-Watching by Satellite

To better understand wildlife, researchers for some time have used radio transmitters to track animals. But conventional units are cumbersome and short-ranged, with signals easily blocked in mountainous terrain. New satellite micro-transmitters are so small that even bantam birds like the peregrines can fly with one strapped on their backs.

Tracking Network

Satellites from a joint U.S. French service called Argos, moving in a low polar orbit, receive the signals

Transmitter size: 0.7 inches x 2.5 inches x 0.6 inches.

Weight: 1 ounce.

Power: 100 milliwatts.

Battery life: 1 year.

Transmission cycle: 8 hours a day throughout the fall mirgration season. Data is relayed every 4 days by electronic mail.

Cost: $4,000 for unit and one year of tracking.

Sample Paths

Here are treks made by two of the falcons, one male and the other female, being studied.