The Wildlife Professional

WILDLIFE IMAGING
Not-So-Candid Cameras
HOW TO PreveNT CAMerA TrAPS FrOM SKeWiNG ANiMAl BeHAviOr

By Michael l. Gibeau, Ph.D., and Cam McTavish

In Canadian forests, the trees have eyes. While doing carnivore research in Canadian Moun- tain National Parks, we find it increasingly common to encounter remote cameras mounted on trees. Growing numbers of wildlife professionals, hunters, and hobbyists are deploying these motion-activated cameras to monitor a variety of wildlife species, believing that this is a non-invasive way to capture natural behavior. Cameras certainly do capture behavior. But is it natural? Not always.

Typically a remote camera “wakes up” when a motion sensor detects the infrared light emanating from an object that’s warmer than the environment, such as a moving animal. The sensor sends a trigger impulse to the camera, which snaps a picture. Some cameras can be programmed to take 10 images as quickly as possible upon receiving one motion trigger. Such motion-detector cameras have helped monitor wildlife for decades (Kucera and Barrett 1993, Mace et al. 1994, Culter and Swann 1999), but in recent years, technological advancements have improved camera function and image quality. Some newer camera models, for example, now have quieter triggers, invisible flashes, larger memory capacity, and more-accurate motion sensors that reduce false triggers. Some are also programmable to adjust focus, contrast, and brightness. With such improvements, cameras have become invaluable tools for wildlife researchers, who need inexpensive and efficient ways to collect data.

Our own experience using remote cameras spans 17 years in eight Canadian national parks, with more than 25,000 camera days to monitor about 34 different species. In our most recent project, which began last year, we’re using remote-camera technology on trail systems in Canada’s Banff, Kootenay, and Yoho national parks to detect large carnivores such as the gray wolf (Canis lupus), grizzly bear (Ursus arctos), black bear (Ursus americanus), cougar (Puma concolor), lynx (Lynx canadensis), and wolverine (Gulo gulo). Data about the seasonal movement, distribution, composition, and abundance of these species help quantify change across a bioregion, and also help fulfill Canadian National Park’s mandate to track indicators of ecosystem health over the long term.

Michael L. Gibeau,
Ph.D., is the
Carnivore Specialist
for Canadian
Mountain National
Parks.
Courtesy of Michael l. Gibeau

Camera-Trap Pitfalls

In doing our carnivore study, however, one issue has been evident and troubling. We’ve observed that some forms of remote-camera deployment prompt a startle response in gray wolves, negatively altering their behavior. Specifically, wolves will stop abruptly if they see a camera flash at night. Individuals will flee, and packs will rapidly disperse, resulting in displacement to the site and significant travel-route changes. This fear-and-avoidance behavior is most pronounced when wolves see a camera flash “head on” as opposed to coming from the side.

Cam Mc Tavish is a biologist and Founder of Mc Tavish Biological Services. Courtesy of Cam Mc Tavish

Researchers have studied numerous species with remote-camera technology including fox (Glen and Dickman 2003), black bear (Bridges et al. 2004), white-tailed deer (Koerth and Kroll 2000), and wood mice (Diaz et al. 2005). In one broad study of vertebrate scavengers in South Carolina, remote cameras monitored 17 different vertebrate species (DeVault et al. 2004). By providing data on population numbers and trends, presence and absence, breeding success, congregation “hot spots,” and the like, such studies can provide the basis for sound, science-based wildlife management and conservation decisions.

Approximately 40 percent of head-on nocturnal wolf images captured by our remote cameras show a distinct startle response as a result of the camera flash. Typically the flash rapidly displaces the first wolf in a pack. Trailing pack members quickly follow, so the camera misses them completely. This happens inside the relatively undisturbed boundaries of national parks, where wolves experience little human manipulation. We therefore suspect that the startle response would be even more pronounced in areas where management is more intense and wolves are more wary.