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Trail cameras provide candid look at wildlife
Researchers benefit from remote cameras
A wolf pack on moose carcass, bears on a beached whale, a wolverine in striking detail, a deer on the trail – motion-triggered trail cameras provide a candid view into the natural world.
Hunters use these cameras to scout game and biologists are discovering applications for research. “Camera trapping” is a growing hobby, enabling wildlife watchers to capture candid still images of elusive animals.
In coming months, the Alaska Department of Fish and Game will feature a gallery of trail camera images on its new website, and submissions are welcome. The gallery will showcase images by the public as well as researchers. See the related article for more information.
Trail cameras have come a long way from the early battery-draining film cameras. The resolution of images and the memory capacity have steadily improved, and batteries are much longer lasting. Today cameras range from about $50 to about $700. High end cameras feature faster trigger speed – the delay between the motion sensor detecting an animal and triggering the shutter (this can be several seconds); better recovery between shots (one to six seconds as the camera processes and stores an image and recharges the flash); flash for night shots in either infrared (invisible to the animals but renders in black-and-white) or LED flash (strobes are almost obsolete); sturdier case and of course, a better quality image.
Researcher Diana Raper has “camera-trapped” wolves, black and brown bears, coyotes, eagles, ravens, marten, and moose. A graduate student at Oregon State University, Raper is working with Alaska Fish and Game to monitor scavenging at large mammal carcasses in the Gustavus Forelands-Glacier Bay ecosystem of Southeast Alaska. She said trail cameras are providing insights into this aspect of food web dynamics that typically receives little attention.
“As a research tool, trail cameras provide researchers opportunities to catch glimpses into the lives of animals like never before,” she said. “We are learning about the different species that utilize these resources, the timing of scavenger arrival at carcasses, and how long the carrion of the different species persists and serves as a resource for the scavenger community.”
She’s also learning about different factors that affect scavenger use of carrion, such as the habitat where the carcass is located or the presence of potentially competing species.
ADF&G Wildlife Technician Jeff Jemison is an experienced photographer and videographer working on several camera trapping projects, including Raper’s project. In addition to the cameras on carcasses, he’s photographed wolverines, and coyote pups at a den site (soon to be featured in the gallery). He said he’s still learning what does and doesn’t work with camera trapping. Some of the problems are related to the cameras being left out for months at a time, others are problems all camera trappers face.
“We’re getting a little water in the cases, even with dessicant packages in there to absorb moisture,” he said. “I think it’s condensation because of the temperature changes between really cold nights and then sitting in direct sunlight during the day. The cases seem to be tight.”
He’s learned it’s best to keep the camera out of direct sunlight. “Face it north, if possible,” he said.
One problem all camera trappers face is false triggers. In the winter, that’s snow falling out of trees, and in spring and summer it’s vegetation blowing on the breeze.
Minimizing false triggers requires trial and error, trimming brush, and careful placement and aim. Jemison jams a two-inch long, dowel-like stick behind the top of the camera and mounts it high enough that it faces slightly downward at the target area.
Researchers are combining camera traps with other technology. Last fall, Fish and Game live-trapped a lone female wolf on the Gustavus Forelands and equipped her with a GPS collar. Jemison is using camera traps to try and learn more about her behavior and status.
“We don’t know if she’s in a pack or running alone, and we’d like to find out,” he said. “We have pictures of two or three wolves from another pack together at carcasses, so we know they’re a pack, but in all the pictures we’ve got of her she’s solo.”
The wolves may be shying away from the camera, depending on whether the flash is visible or not. Canadian biologists Cam McTavish and Michael Gibeau have worked with remote cameras for 17 years, monitoring 34 different species. They found that wolves in particular can be sensitive to flashes and will avoid night-firing cameras. They did not find that other animals were adversely affected.
Jemison said the Gustavus wolves don’t appear to be bothered by the flash, and the images support this (soon to be featured in the gallery). “We have lots of wolf shots and they seem to ignore the flash,” he said. “If we did have infrared, I’d certainly use them.”
State biologist Rod Flynn is live-trapping wolverines in the Berners Bay area north of Juneau, intending to GPS collar the animals, and recently equipped all eight live traps with cameras to document activity at the trap sites. Additional camera traps are being placed in the area to record the presence of wolverines, and to document the possible presence of fishers. Fishers are a cat-size cousin to the wolverine. Only three fishers have been documented in Alaska, all in this general area, and a photograph would be an important documentation.
Biologist Audrey Magoun studies wolverines and has been working with trail cameras for years. She recalled her frustration with the first cameras. “I started out in Ontario using film and alkaline batteries, and we got one picture in all that time of trying with those early cameras.”
Magoun recently published a book titled “Using Motion-detection Cameras for Photographing, Identifying, and Monitoring Wolverines.” The book is both a how-to guide for researchers and a documentation of her recent wolverine work with ADF&G near Petersburg in Southeast Alaska. She also has a related article coming out in April in the Journal of Wildlife Management.
Magoun found that wolverine’s markings do not change appreciably over time, and the pattern of light and dark fur on their underside is particularly distinctive. Biologist use photographs to identify individual tigers and spotted cats by their unique markings, but Magoun said that requires photographing both sides.
Photographing a wolverine’s underbelly may seem like a daunting task, but Magoun developed a technique using a camera station and a “run pole,” a bait station that encourages the wolverine to pose in the most advantageous position.
“Wolverines are the perfect animal for this,” she said. “It will stand up readily, with its head looking up, so you can position it exactly where you want it. You can tell if its male or female, and if its lactating.”
Magoun fine-tuned her station design and her identification techniques with 20 or 30 captive wolverines in a facility in Washington, where she could cross-reference and verify specific animals and gender. In 2009 she began using “hair snags” at the camera stations to collect hair samples from the wolverines, which provide DNA for additional cross-referencing.
In 2008 Magoun had about 47 cameras out on about 35 sites, across an area of about 2,500 square kilometers. She monitored the cameras every two weeks, using boat and helicopter to access the sites. In 2009 she reduced that to the most reliable sites, about 27, and doubled up the cameras at each site.
That second camera provided back up, and also allowed her to see if multiple animals were visiting the site. She wanted to know if animals were hanging back, too timid or suspicious to approach the set up, or if females were bringing young and keeping them close - but not too close. Some cameras used an infrared flash, which animals can’t see, and she was able to compare the cameras.
The infrared images are rendered in black and white, and proved less useful for photo-identification than the color images.
She positively identified 21 individual wolverines, with a few more that she wasn’t positive about. She determined the wolverine density is about one animal per 100 square kilometers, which is fairly high. “It’s similar to the density in Sweden, where they’ve studied wolverines for years,” she said.
Magoun said she did not think the flash intimidated the wolverines. “My guess is that most wildlife gets used to the flash,” she said.
She said animals see lightning in nature, and there were elements at the sites more daunting than the flash. The camera, and the whole artificial apparatus constructed with metal and plastic, with bait hanging from a cable, was potentially off-putting. “They were a little startled by the flash the first time, but they overcame that pretty quickly,” she said. “The toughest thing was the set up for hair snagging, they seemed more intimidated by the alligator clips.”
She said it all depended on the animal. “Some show up the first time and within four seconds they’re up there. Others will come multiple times and look it over. One animal never went up the run pole, she came many times, but she was timid about the set up.”
Another animal came for three years before finally overcoming her shyness - nursing wolverines are hungry. “Once she started lactating she lost her cautiousness,” she said. “Some of the females feeding young are less cautious, they’re hard up enough, but they were really shy for a couple years, just looking the whole set up over. Once they start they’d get really bold, but if they went to a new camera site, they’d go through the whole caution thing again. The new set up and new spot – they didn’t generalize.”
Magoun said she photographed a lot of marten, the wolverine’s smaller cousin. “This system works really well with marten, I had lactating marten standing up, they’re really bold. I had lots of black bears come in, weasels, eagles, Steller jays, and moose were very curious. I had one moose come by all the time, he’d visit the site and get his picture taken.”
Black bears were only occasionally problematic, but brown bears are known to be pretty destructive of trail cameras. They are curious and attracted to plastic and rubber, and bite the cameras. “You’d need metal bear boxes for the cameras if you were doing a grizzly bear study,” Magoun said.
The rare problem with black bears resulted more from their affect on the wolverines than the cameras. Magoun knew the lactating wolverines had young, but she did not photograph the young until late summer. “They are mobile, but I think the mothers are cautious about bringing them because other predators could be around. One quit using a site when a black bear began visiting.”
She said black bears would climb up the run pole and pose just as the wolverines did, but they were harder to identify by picture because their fur and hair changed over the summer as they rubbed and shed. “Some I could tell apart because of a nicked ear or something,” she said. “We talked about ways to use this for bear research, some way to mark the bear with paint or something.”
Magoun used two kinds of cameras, Trail Watchers and Reconyx, and both are in the $700 range. Reconyx have an infrared flash, and tended to work better at temperatures below -10 (because they use a fixed-lens camera), but Trail Watchers were her mainstay. Trail Watchers are custom made in Georgia by Dave Helmly, and she found him responsive and reliable. “He wants to test a new model at lower temperatures, so he’s sending me one to try,” she said. “The technology is changing so fast with these cameras.”
Helmly uses off-the-shelf 12 megapixel point-and-shoot Sony Cybershot cameras and builds the electronics. “They give beautiful, sharp pictures,” she said. “I’ve had some of these Trail Watchers out for five seasons, some winter and summer, and they still work great. That’s really unusual.”
Magoun has spent this past winter in Northeastern Oregon, looking for wolverines in the Wallowa Mountains. She’s deployed 12 cameras, but she’s been dealing with snow storms, high winds, avalanche danger and the difficulty of accessing the Eagle Cap Wilderness. “Yesterday I got blown over on my skis in a blizzard,” she said. “It’s not like Petersburg.”
“Using Motion-detection Cameras for Photographing, Identifying, and Monitoring Wolverines,” can be found at: http://www.blurb.com/bookstore/detail/1914572
Riley Woodford is a writer and producer for the Division of Wildlife Conservation. He’s camera trapped since 2000 and is ready to upgrade.
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