Here on BCI, Kays and Martin Wikelski of Princeton University are testing a groundbreaking animal-tracking system called the Automated Radio Telemetry System, or ARTS. With funding from the Levinson Family Foundation and the National Science Foundation, the system was installed by the Smithsonian Tropical Research Institute, which has run a research station on BCI for 82 years. Ocelots and agoutis were the first species to put ARTS through its paces.
Traditional wildlife radiotelemetry requires several researchers to scramble about with receivers to triangulate the position of an animal that had previously been trapped and collared with a transmitter. In contrast, ARTS consists of seven permanent radio towers positioned across the island. They pick up and relay signals to computers that constantly monitor dozens of animals. "You can gather more data in one week than you can in years of traditional telemetry," says Kays.
If he wants to know the daily activity schedules of his subjects (as well as of other species the system now tracks, such as sloths, monkeys, and opossums), he can simply scan the computer. One program produces a graphic that shows when the animals are active. This allows researchers to keep track as ocelots rouse themselves, typically around 6 p.m., to go on a prowl that will likely continue until morning. ARTS also constantly maps the locations of the cats, which has helped scientists learn that the average home range of a male BCI ocelot is 1.4 square miles; for females, it's about 0.6 square miles. This spatial monitoring becomes especially exciting, and scientifically illuminating, in the rare case when two collared animals meet and interact.
Useful as it is, "technology can't replace fieldwork," Kays says. He and his colleagues also use traditional methods like collecting scat and searching for paw prints. Their goal: to learn more about the importance of predators to ecosystem health. For instance, if ocelots were to become extinct on BCI, unchecked rat or agouti populations that devour seeds could wipe out some plant species.
Ocelots do face threats from poaching and habitat destruction. But happily, now that hunting the cats is illegal in most of their range, there's little danger the 1.5 million to 3 million ocelots living in the Americas will disappear anytime soon. In many parts of the tropics, hunting has decimated populations of jaguars and pumas, the Western Hemisphere's largest feline predators, raising ocelots' status a notch in the ecosystem big shoes to fill for the forest cats.
"They may now be the dominant predators in many areas across the tropics," Kays says. "To what extent can they play the balancing role of large predators? This is a question we want to answer."