Radio transmitters, sometimes called "pingers," are a classic monitoring method. Powered by batteries, they transmit very high frequency signals that are picked up by antennas or satellites. Until recently, the batteries' weight and size couldn't be reduced enough to use transmitters on small animals and fish. But now, says Doug Bonham, a freelance circuit-board designer based in rural Montana, a few companies are using "spectacular miniaturization" to create transmitters that weigh less than half a gram -- "just a speck" -- that can be glued to dragonflies. Generally, these devices transmit only basic data to preserve the battery's power -- signaling the animal's location every few hours, for instance. Argos, a joint U.S.-France satellite system dedicated to receiving wildlife transmissions, was perfected in the 1980s and now coordinates with the GPS system. GPS satellites send down signals that locate radio collars precisely, and then the collars transmit their locations to the Argos satellites.
The most scrutinized river
The Columbia River is the world's most highly monitored ecosystem, due to pressure from environmentalists, tribes and fishermen, and funding from the Bonneville Power Administration, the lead federal agency in the management of the river system's 35 major dams. In an average year, more than 2 million salmon and other fish in the ecosystem are injected with "PIT tags" -- Passive Integrated Transponders, also called microchips. Roughly the size of a grain of rice, a PIT tag doesn't transmit a signal, but each tag has a unique number that specialized antennas can detect through a few feet of water. Hundreds of these antennas are installed in the dams, tributaries and other key sites to track fish migrations between the headwaters and the ocean, and since 1987, the data from more than 31 million PIT-tagged fish has been collected in a huge database. "I had a vision, but people thought it was a fairy tale," says Earl Prentice, a retired NOAA fisheries biologist who pioneered the PIT-tag system on the river in the 1980s. Now Prentice foresees an "astronomical expansion" of PIT-tagging on many species around the world. Dean Park, the head of Boise, Idaho-based Biomark, Inc., which has dozens of employees tagging fish and installing antennas, adds, "It's an exciting time for our company."
Listening to migrators in the ocean
An audio technology monitors West Coast salmon after they leave the rivers. It consists of "acoustic tags" -- sound-emitting devices attached to thousands of fish -- and specialized listening devices, or "receivers," tethered to the seabottom in key sites along the Continental Shelf, from California to Alaska. The main effort -- the Pacific Ocean Shelf Tracking Project, or POST -- used funding from the Sloan Foundation to install more than a dozen receiver arrays from 2002 to 2010. But federal agencies and Congress refused to pick up the slack after the foundation's funding ended, so now only a half-dozen POST arrays are still operating, says John Payne, a biologist based in Washington state. POST discoveries include the troubling fact that many of the steelhead migrating through Puget Sound die before they reach the ocean, possibly due to pollution in the sound. Despite all our technology, Payne says, "we know so little" about the rapidly shifting interactions of species and environmental conditions caused by climate change.
A better bear trap
The Automated Bear Trap is a new invention from Alter Enterprises, a small Missoula, Mont.-based wildlife-monitoring company. It resembles a traditional culvert-style trap, but company head Ryan Alter added a camera, sensors, automated controls, a solar power cell and a transmitter that links to satellites or cell-phone networks. When an animal is trapped, a biologist can receive a phone message in which a female voice says: "Event notification: Bear Trap #1 door has been triggered. Please press 3 to acknowledge." Then the biologist can use the Internet to view the animal. If it's a dog or any other animal that was trapped unintentionally, the biologist can release it and reset the trap remotely. "You can do that from anywhere in the world," Alter says, and it's more efficient and safer for both the animals and the biologists. Alter plans to sell his automated traps for $30,000 to $50,000, depending on which technologies the customer wants. Alter's other projects include creating an artificial bear den rigged with a videocam, which reveals that hibernating bears don't sleep all winter, and rigging 200 acres with dozens of cameras and sensors that record the activities of many species for a wealthy landowner.
Many helping hands
Biologists have devised a variety of techniques to monitor and protect osprey. The fish-eating birds were nearly eliminated in the Northern Rockies by DDT, a pesticide that drifted from crops into streams and up the food chain. Populations rebounded after DDT was banned in the U.S. in 1972, with additional help from power-company biologists who constructed osprey nest platforms that lure them away from power poles, where they're often electrocuted. About 80 percent of Montana osprey now nest on manmade platforms, says Erick Greene, a University of Montana wildlife biology professor. But the birds seem to be declining again, so Greene is part of a team monitoring about 200 nests, tracking birth rates and chick survival and taking blood samples. They use "bucket trucks" to reach the nests, small remote-controlled helicopters outfitted with cameras, and "nest cams" that stream live video. They've discovered that some osprey chicks have toxic mercury in their blood at levels hundreds of times higher than the human-health standard, probably due to runoff from old gold and silver mines and emissions from coal-fired power plants. "Monitoring the osprey chicks is telling us, what people do today (generating mercury pollution) will be around for a long, long time," Greene says. The biologists also remove the baling twine that osprey weave into their nests, and untangle chicks that would be strangled by it.
Geolocators and accelerometers
Today's miniaturized wildlife technology includes "geolocators" that are small enough to work like "backpacks" fastened to songbirds. When the birds migrate from North America to Latin America, the geolocators record the times of each sunset and sunrise -- data that indicate each bird's rough location each day. Other devices called "accelerometers" record the movements of animals' bodies in activities like chasing prey or fleeing from predators, allowing biologists to calculate "energy budgets" (the amount of energy animals spend on different activities).
Even with all the technological advances, many biologists are do-it-yourselfers, making some of the monitoring devices they use. They find it's often cheaper than buying from manufacturers, and they can customize the devices to meet specific needs. In addition, conditions are stressful for any technology used in the wild; things frequently break, so biologists have to be handy tinkerers, says Brad Shepard, a longtime federal fish biologist who's now with the Montana office of the Wildlife Conservation Society. For instance, in a photo above, two researchers, Ethan Kleekamp and Jeremy Plauger, used hand-held antennas built by Shepard on a mission to locate PIT-tagged cutthroat trout that were reintroduced in Cherry Creek, on a Montana ranch owned by billionaire conservationist Ted Turner, last September.