How to Spy on an Albatross - tracking birds

National Wildlife, Feb-March, 1999

With the help of tiny transmitters and orbiting satellites, scientists are discovering that birds have some astonishing destinations

There are stories--perhaps apocryphal, perhaps not--about ultrasecret spy satellites that can discern small details on Earth. They might, for example, count the albatross nests on Tern Island, an oddly shaped speck of land in the North Pacific Ocean, from 500 miles high. For the record, some 3,500 pairs of Laysan and black-footed albatrosses use Tern, part of the Hawaiian Islands National Wildlife Refuge, as a nursery. However, that number comes from a scientist's informed estimate, not from an intelligence agency.

Still, the Tern Island albatrosses are being spied on from space. The satellites in question, however, are dedicated to monitoring Earth's environment, not military and terrorist activities. And the information comes in the form of pulses of data from bird-based radio transmitters, not super-sharp pictures. For Tern is the site of an important study using satellite telemetry--a fast-evolving technology that has revolutionized conservation ornithology in a few short years--to track the travels of parent albatrosses as they fly far and wide in search of food for their earthbound offspring. Often those trips take them to dangerous waters.

In the process, Tern also has become a virtual science classroom for thousands of schoolchildren from Hawaii to Pennsylvania who are hands-on participants via the Internet in Wake Forest University's Albatross Project, led by biologist Dave Anderson. Like the grown-up researchers at the North Carolina campus, the kids learn where "their" albatross went today by plotting coordinates relayed from Argos System satellites that scan for signals from the birds' backpack transmitters on every pass.

One Laysan albatross, they determined, made four treks to the vicinity of Atka in the Aleutian Islands, a straight-line, round-trip distance of 4,000 miles--each time bringing home a liter of high-energy fish oil for its single chick. "That's a long way to go for takeout," quips Anderson, adding, "We never imagined that a bird would fly that far north from Tern." At the same time, a black-footed albatross flew 24,840 miles in a three-month period on round-trips of as long as 28 days to foraging waters off the northern California coast.

Tern Island, lying 675 miles northwest of Honolulu, is an ideal base for Anderson's study because of its accessibility to birds and biologists. From the air, it resembles an oversized aircraft carrier run aground on a treacherous atoll. The scenario is plausible: Tern is part of French Frigate Shoals, discovered in 1786 by a Gallic navigator whose two ships came within a tenth of a mile of smashing onto the reef, as an American whaler did 80 years later.

A reality check finds that Tern is little more than a 3,100-foot-long airstrip, built on the island out of crushed coral in the early months of World War II and serving much the same purpose as a flattop. The U.S. Navy's Seabees also did a big favor for the albatrosses when they enlarged Tern. These slender-winged birds are indescribably graceful as they glide over the ocean waves for months on end, but they need a long and uncluttered runway for indescribably ungraceful takeoffs and landings during the time when they're raising chicks.

Like similar projects involving other birds large enough to carry a platform transmitter terminal or PTT, as the device is known, the Tern Island study is partly about finding the answer to a question as old as human curiosity: Where do birds go when they leave their nesting places?

In the case of swallow-tailed kites that breed in Florida, their migration route and ultimate destination were unknown until 1996, when biologist Ken Meyer of the Avian Research and Conservation Institute in Gainesville first deployed PTTs on seven birds and tracked their 5,000- mile journey through Central America and onward to southeastern Brazil. American bitterns wearing transmitters on a bib instead of a backpack will tell John Toepfer, a biologist in Plover, Wisconsin, where this secretive marsh bird spends the winter.

Toepfer, whose work is partially funded by the U.S. Fish and Wildlife Service, uses a mirror and a tape recording of the bittern's oong-ka- choonk vocalization to lure the territorial birds into a trap. "The bittern sees itself and attacks the mirror," Toepfer explains. "It works 7 out of 10 times." (Hanging the transmitter around the neck is necessary because a bird's welfare is the first concern. Bitterns have a ridge on the back and a harness would roll and cause saddle sores.)

Guy Morrison, a biologist at Canada's National Wildlife Research Centre in Hull, Quebec, hopes to "crack the abiding mystery" of where and why Hudsonian godwits pause on their fall flight from breeding areas around James Bay to wintering places along the coast of Patagonia and Tierra del Fuego. "There's a gap of about six weeks between the time the birds leave Canada and when they arrive in Argentina," he says. "My guess is they stop somewhere in Amazonia. The rivers are lowest at that time of the year, and the godwits may be congregating on big sandbars."