Elephant Ears

You may not see Ghana’s forest elephants, but you can hear them—if you know how to listen.

By Beth Saulnier

The African forest elephants in Ghana’s 300-square-kilometer Kakum National Park rarely reveal themselves. They’re so reclusive, in fact, that only one photograph of them is known to exist. And, to be specific . . . it’s a shot of one animal’s rear end. But there are elephants there, between 150 and 200 of them. Conservationists got that rough count through a laborious and unappetizing process called dung counting. But recently, the presence of elephants in Kakum was confirmed because of another fact of nature: even if you can’t see the elephants, you can hear them—if you know how to listen.

And knowing how to listen (or, rather, to record) is the specialty of a 24-year-old electrical engineer named Robert MacCurdy. MacCurdy ’99 is a research associate in the Cornell Laboratory of Ornithology’s Bioacoustics Research Program, where scientists use sound to study animal populations that are difficult to observe the old fashioned way: whales, night-migrating birds, and those clever elephants. “Basically,” MacCurdy says, “I’m the design guy who takes care of all of the audio recording stuff for projects that come along.”

That recording stuff is both simple and devilishly complicated. The sounds—be they birds’ communicating chirps, whale songs, or elephant calls—are recorded with an analog microphone, then filtered and amplified for digital storage. The digital recorders, which store the information to a hard disk, were designed by Thomas Calupca ’91 EE; MacCurdy works on the rest of the system. And while that process may sound fairly straightforward, the circumstances aren’t.

MacCurdy has to design so-called “autonomous recording units” that work under battlefield conditions: hundreds of feet beneath the sea or in the blazing African heat. The elephant-sound recorders, for example, had to be light enough to carry, hardy enough to withstand changing environments, small enough to hide from both animals and poachers, and equipped with enough power to last for months. “It’s important,” bioacoustics research associate Katy Payne says of the effort, “because we need to find out how many forest elephants there are in the world, and what condition the populations are in.” It was Payne who, back in 1984, first suspected that elephants use infrasound—sound below the range of human hearing—to communicate over long distances. That discovery may offer solutions to long-standing questions about elephant society, such as the how males find mates, and how separated family groups coordinate their movements.

The Elephant Research Project, a cooperative effort among researchers around the world, bases its techniques on the Lab of Ornithology’s work with whales. Its first field effort, which looked at savannah elephants at Etosha National Park in Namibia, was conducted in 1999. The study in Ghana used MacCurdy’s microphones to collect two months’ worth of data, which were then compared to the results of a simultaneous dung count to see if the acoustic method was reliable. It was. “Rob jumped in to fill a need and did so with great competence and energy,” says Payne. “He made a tremendous contribution.”

MacCurdy went to Ghana in May 2000 to work with an international team of rangers, conservationists, and scientists including Richard Barnes, the University of California at San Diego elephant researcher known as the father of dung counting. Since the recording units are custom-made, it’s often essential to have an engineer on site to deal with whatever technical issues crop up. MacCurdy did some additional design work there, with intermittent power and no diagnostic equipment beyond a laptop and a borrowed signal generator. “I wish I could clone him,” says Bioacoustics Research Program director Chris Clark. “Rob is just this wonderful combination of having a really good personality—easy to talk to, a sense of humor—and being very intelligent and well-educated in the engineering and physical sciences.”

MacCurdy is also a serious jock; he has a kayak, rock-climbing gear, skis, a snowboard, and two mountain bikes. And while that might not matter much at the worktable, it made big difference in the field. His enthusiasm for outdoor sports helped prepare him for the daily hikes into the Ghanaian forest, toting the recorders and their battery packs (totaling 50 pounds) along with an awkward homemade, two-meter bamboo ladder. “It was tough,” says MacCurdy. “In some places visibility was less than four meters. You couldn’t see the guy in front of you because it was so thick. Navigation was basically only manageable with a compass and a GPS. Without that, you could get totally lost.”