What Do We Really Know About Predator Behavior?

With a little practice, researchers can tell if a coyote ate a vole or a mouse simply by examining parts that passed through the coyote.
What Do We Really Know About Predator Behavior?

We know a lot about coyotes, bobcats and other predators. For example, coyotes kill and eat many deer fawn in Georgia. In western states, black bears migrate hundreds of miles between their summer and winter ranges. Bobcat populations have dwindled in central Illinois due to habitat loss.

So how do we know? We know because of the men and women who devote their lives to studying wild animals, including predator species. Scientists at universities, government agencies and non-profit organizations use a variety of methods and tools to peek into the private, secretive lives of a variety of animals.

Much of their knowledge is gleaned from time in the field and evaluating past research. These days, however, scientists are learning more than ever by using tools that weren’t available 20 or 30 years ago. One such tool is DNA analysis, which has helped scientists understand not only how coyotes made their way to the eastern United States, but also whom they mated with along the way. As it turns out, some bred with wolves and others with domestic dogs. That explains the subtle dog-like appearance of some eastern coyotes and the larger size, which is likely a result of introduced wolf genetics. In another study, bobcat DNA gathered through hair samples at bait stations during a West Virginia study was used to determine population densities, home ranges and family history.

Scientists are learning more about predators thanks to technology and better information. Photo: Georgia DNR

“Some studies have used carbon-nitrogen signatures to determine the amount of anthropogenic (human) food in an urban coyote’s diet,” says Berry College associate professor of biology Dr. Chris Mowry, director of the Atlanta Coyote Project. “There’s no question modern science has opened a lot of doors for the research community.”

Arguably, no other tool has made the job of researching wildlife easier than global positioning systems. The technology, invented in the early 1970s, uses satellites, receivers and computers to pinpoint locations virtually anywhere on Earth. Some GPS units weigh as little as a third of an ounce, small enough to use on birds and small mammals. Batteries can last for two or more years. Scientists can track an animal throughout its life stages, pinpointing its location to within a few yards at any time. And they don’t even have to leave their office.

“I can’t say that GPS technology is any better than VHS as far as tracking animals, but it has certainly opened new doors. Determining an animal’s location is more precise with GPS and we can track an animal’s path throughout the day without actually following it around in the field,” says Joseph W. Jones Ecological Research Center ecologist, Dr. Mike Conner. “That means we aren’t spending money on gas and manpower, and we don’t have to be out there in inclement weather or otherwise dangerous conditions to learn about an animal’s activity.”

Biologists have used GPS devices to track just about every type of predator in North America. They not only show an animal’s location, they can help researchers better understand preferred habitats, movement rates and travel corridors. A GPS device can even help scientists find a predator’s kill site. Some are equipped with a variety of other tools that relay an animal’s heart rate, travel speed and body temperature.

“There are so many things we can learn from some device attached to a collar,” says Conner.

First, though, researchers have to catch the animals before they can fit them with any sort of tracking device. Instead of relying on modern technology, scientists resort to methods that have been used in America since for hundreds of years. Leg-hold traps are a vital tool in catching animals in order to study them. In most cases, scientists hire local trappers to do that, but a few with trapping experience catch their own.

“It can be stressful or even physically damaging to an animal if it isn’t done properly. It is also exceptionally time-consuming. Coyotes are not easy to catch, which is why we contract with someone who is experienced,” says Mowry.

That’s one reason he is using remote cameras for an increasing amount of his research. Popular among deer hunters, trail cameras assist Mowry to help determine population densities, travel corridors and other valuable information without physically capturing an animal.

“The use of trail cameras for research is still young,” says Conner. “I don’t think we have figured out just how beneficial they can be for learning about wildlife yet.”

Technology certainly plays a significant role in research, but much of what scientists know about our favorite predators is a result of on-the-ground experience. There’s no better example than research that examines the diets of coyotes and other predators. Mowry has been involved in coyote diet analyses in Yellowstone National Parks, where he and his students sifted through scat in order to determine what the animals had been eating. It isn’t the most glamorous work, but it helps answer some important questions.

“We basically wash it in a strainer, dry it and then separate the various items that remain. We are looking for such things as jawbones, hair, feathers, claws, scales and other identifiable items,” he says. “The research was attempting to learn how the reintroduction of wolves affected coyotes and their food sources. We were able to examine coyote scat that had been collected in the park prior to the reintroduction of wolves.”

With a little practice, researchers can tell if a coyote ate a vole or a mouse simply by examining parts that passed through the coyote. It is painstakingly tedious and perhaps a bit nauseating, but it is necessary to learn about predator diets.

“We can use DNA analysis to determine what type of animal a coyote ate, but mostly it is a matter of examining the contents of scat samples,” says Mowry. “It is time-consuming, but that’s part of the process.”

Some studies take years to conclude, but the field and lab work researchers undertake doesn’t require just time. It takes money. Not only do they have to buy expensive equipment like GPS collars, which can run upwards of $2,500 each, they have to put gas in their trucks to complete fieldwork. Researchers pay trappers to catch the animals they study too, and graduate students typically receive a stipend during the study itself. In fact, those graduate students are an integral part of any study. They not only do most of the fieldwork, they also do much of the data entry and analysis.

That’s why a single multi-year research project can cost tens of thousands of dollars. Mowry uses trail cameras, which are cheaper than GPS equipment, and he has used VHF tracking devices, as well. They require more time in the field and aren’t as accurate as a GPS device, but the data can be equally valuable. VHF devices are also less expensive than a GPS unit, typically $200 to $400.

Funding comes from a variety of sources, says Mowry. Grants from universities are common, but so are grants from private foundations, which are often funded by wealthy individuals to encourage research.

“Crowdfunding is becoming more popular. Basically, our funding comes from a variety of means. We kind of scrape it up wherever we can,” adds Mowry.

So what do researchers do with all the data they gather? In most cases, it is compiled, analyzed and then detailed in a lengthy paper written for other scientists. Those papers can take months to write before going through a peer review process that helps lend credibility to the study. Once it passes scientific scrutiny, that paper may be published in a professional journal like The Wildlife Society’s Journal of Wildlife Management.

Some of it never makes it that far. That’s okay, though. Published or not, the data scientists gather helps shed light on the lives of those animals we love to hunt. The more we know, the better our chances of success.

Featured image: iStock


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