The closest that park officials often get to catching poachers is stumbling across carcasses days or weeks after the culprits have fled the scene. Now a new surveillance system may help locate, track, and intercept poachers before they strike.

The system consists of a network of foot-long metal detectors similar to those used in airports. When moving metal objects such as a machete or a rifle trip the sensor, it sends a radio signal to a wireless Internet gateway camouflaged in the tree canopy as far as a kilometer away. This signal is transmitted via satellite to the Internet, where the incident is logged and messages revealing the poachers' position and direction are sent instantly to park headquarters, where patrols can then be dispatched.

"[This system] is a force multiplier," says Steve Gulick, an electrical engineer and director of Wildland Security, a Brooklyn-based organization that develops antipoaching technology. "It could potentially make the patrols more efficient. They would know where to go and could mount a real-time response."

Since the early 1990s, Gulick, a self-confessed "biologist wanna-be," has been using his talents to develop gadgets for biological research and conservation projects. A couple of years ago, Gulick developed motion-triggered cameras for biologists studying chimps' tool use in the Nouabalé-Ndoki National Park (NNNP) of the Republic of Congo. The surveillance system, dubbed TrailGuard, is his latest project. Gulick was inspired to develop the system after watching, frustrated, as "patrols returned time and again without any apprehensions--but with bags of animal body parts."

The U.S. Fish and Wildlife Service is funding the first field test of TrailGuard within the Goualougo Triangle--the southernmost corner of the NNNP. The site is a prime locale for studying chimps and is unusual because, according to researchers currently working there, it has remained intact and free from hunters for hundreds and possibly thousands of years. "We have not found any indication of illegal entry and poaching in the study area where we are habituating wild chimpanzees," wrote Crickette Sanz and Dave Morgan in an e-mail from Congo. Sanz is an anthropologist at the Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany, and Morgan is a field researcher with the Bronx-based Wildlife Conservation Society, in New York.

But, they say, the area could be threatened by illegal hunting as logging operations move closer: the research team has already identified signs of illegal entry in a region just north of the Triangle.

"This indicates that consistent surveillance and long-term protection efforts are needed in even the most remote areas," wrote Sanz and Morgan.