At a study site in Kasigau, Kenya, subsistence farmers scratch out a living on dry, nutrient-depleted soil. The small farms, called shambas, rely on rain and methods in use since the beginning of agriculture to produce corn, lentils and cowpeas.
Wildlife —from elephants to monkeys and small antelope — raid these crops. By doing so, they take food off farmers’ tables or, in extreme cases, cost a grower his or her livelihood for a full season.
The problem and the basic solution are ancient. Farmers plant crops, animals raid them, and farmers put up scarecrows to frighten off the marauders. Now, researchers are combining common technologies with insight into animal behavior to update the ancient scarecrow in the hopes of helping the most vulnerable of growers.
In April, scientists from Western Kentucky University and African collaborators plan to begin another field season, developing motion-activated scarecrows intended to drive off crop-eating animals with a barrage of random cues that trigger deeply ingrained fears.
In addition to devices being tested on smaller animals, researchers are developing special tracking collars for elephants that will activate scarecrows when the massive animals draw near.
“We are not looking for an all-or-nothing solution,” says Michael Stokes, a wildlife ecologist who, with elephant expert Bruce Schulte, is leading the project. “If we can reduce crop damage by 10 percent as crops are coming to ripeness, we have been successful.”
Creative iPod use
When triggered by the system’s motion detector, the scarecrow devices, which look more like collections of spare parts than Wizard of Oz characters, can emit an assortment of scary sounds stored in a hacked Apple iPod portable media player. “It’s probably the most unique use you have ever seen of an iPod,” Stokes says.
Lions’ roars, distress calls and other potentially alarming sounds may be re-enforced by an emergency vehicle-type strobe light, and even a whiff of leopard urine released from a device inspired by a Glade automatic air freshener.
The project has evolved since being awarded funding from the National Science Foundation and the Bill & Melinda Gates Foundation’s BREAD program in 2010. Drought starved African buffalo, and the floods that followed washed away bush pigs, two crop raiders upon which the researchers hoped to focus. So far, they have collected most of their data with porcupines, small antelope known as bushbuck, vervet monkeys and baboons.
“The conclusion we have come to right now is that some animals are hard to deter and other animals are pretty easy to deter,” Stokes says. Porcupines and bushbuck are in the latter category. “As long as you make them aware they are in danger they go away or you can distract them for some significant amount of time.”
Traditional scarecrows, as well as other animal-repelling measures, often loose effectiveness over time. The problem: The animals become accustomed to the straw man, the 3-D owl model, or other deterrents. To address this issue, the automated scarecrows randomly generate stimuli intended to keep the animals off guard, and the devices are intended for use only at times when the risk of losses is highest.
The researchers are incorporating cues that evolution has taught foraging animals to fear, like the scent of predator urine. Eventually, they hope to use cues specific to particular species.
Collars for elephants
Although the automated scarecrow project is intended to help small farmers like those in Kasigau, much of the fieldwork has taken place on larger farms in South Africa for logistical reasons, including more amenable wildlife laws and less of a language barrier.
However, researchers developing a system to address forays by the most feared crop eater — elephants — are working in Kasigau. These animals can be destructive and dangerous, sometimes killing people. But to locals, their infamy sometimes outdistances their actions. “Farmers tend to heap all crop-related damage to elephants even when other animals are involved,” Simon Kasaine, a Western Kentucky University graduate student writes in an email.
Conventional protections like electric fencing are prohibitively expensive for subsistence farmers who instead light fires, throw things and undertake other dangerous, taxing measures, he says.
Kasaine and his assistant have identified hotspots for human-elephant conflict in Kasigau. They are using these to determine exclusion zones, which they plan to monitor and enforce by putting transmitter-equipped collars onto the animals.
“Currently, we are focused on identifying elephants (individuals or groups) that are notorious crop raiders who will be our main targets for collaring,” Kasaine writes.
(Vervet monkeys make off with oranges they raided from an orchard. Courtesy Merrie Richardson.)
Elsewhere in Kenya, in Kitengela, a Maasai boy named Richard Turere designed and built a flickering light to keep lions away from his family’s cattle, an invention he described at a TED talk. Turere’s system is likely effective because the lions have learned to associate lights with attacks by people who kill them for eating their cattle, says Stokes, who is pessimistic about the lions’ future in this area.
The underlying problem for the lions in Kitengela as well as for wildlife caught eating crops elsewhere, is one of human population growth and expansion into once wild areas.
“A, there are no easy answers; B, there are no easy answers; and C, there are no easy answers. And you get the idea,” Stokes says.
The problem isn’t unique to Kenya; globally, habitat destruction due to population and economic growth overwhelmingly drives the loss of biodiversity, he says.
Top Image: When a motion sensor is tripped, this automated scarecrow emits a random combination of sound, light and scent to distract animals set on eating a farmer’s crops. Courtesy Merrie Richardson.