Friday, 27 Jul 2001
MINERAL, Calif.
Fridays are a good day to look back over the week, literally, because on Fridays we get our photos back from the TrailMaster automatic camera stations that we checked on Tuesday.
We had four pairs of camera stations set out in Lassen Volcanic National Park and the surrounding Lassen National Forest, so we had eight rolls of film developed. Flipping through the photos for the first time is like opening Christmas presents: You never really know what you're going to get, and the initial suspense and excitement are often followed by disappointment.
Here's a usual batch of photos: One shot of me looking dorky as I make sure the equipment is working right. Five shots of the bait drying in the sun. Two shots of a squirrel checking out the bait drying in the sun. A bird. Squirrel, squirrel, squirrel. A close-up of a deer's butt at 2 a.m. Five shots of the bait glistening in the dawn. More squirrels. Then finally, maybe, something interesting, like a bear or a pine marten or even one of the Sierra Nevada red foxes we're looking for. Then more shots of deer or squirrels and a final picture of something that looks like a supernova, which happens when a camera's batteries die.
Red fox peering out of red fir grove.
Photo: John Perrine.
This week's photos are par for the course, except for one neat photo of a coyote. Of our eight camera stations, only one photographed a red fox. On one hand this is good, because we knew one of our collared red foxes was in that area -- and the camera station detected it. But on the other hand there don't seem to be any red foxes in other places. This is our second summer using these camera stations, and we have yet to detect a red fox outside of Lassen Park.
What does it all mean? At this stage of the game, we're flying a bit blind, like assembling a jigsaw puzzle without looking at the photo on the box. But, eventually, a picture will begin to come together. Our five radio-collared foxes have taught us that, in the summertime, each red fox has its own territory of about four square miles. That's a lot of turf for an animal the size of a house cat. This implies that one fox needs that much space to find enough food and other resources to keep it alive. In the wintertime, our collared foxes leave Lassen Park entirely, heading south into Lassen Forest. The one collared fox that didn't move out of the park didn't survive the winter. This suggests that, once the snows start, the foxes just can't make a living at the higher elevations in the park. Once the snows melt in the spring, though, the foxes head right up to the park, often to the same places where they spent the previous summer. The photos from our camera stations support this pattern of seasonal movements: In the summer, we detect a few foxes in the park and none in the forest, while in the winter, we detect those same foxes down on the forest instead of up in the park.
Clockwise from top: John Perrine, Whitney Meno, Kristin Young, Frank Wolff (a researcher from Europe visiting for the day), and Samantha Ratti.
Photo: John Perrine.
Maybe this movement pattern is driven by a lack of food. Maybe it's driven by competition with bigger carnivores, such as coyotes and bobcats, both of which may kill red foxes. Or maybe it's something else entirely. But the end result is that there aren't nearly as many red foxes in the Lassen area as we thought. Any management plan to conserve these rare foxes is going to have to take into account the foxes' seasonal movements among the national park, national forest, and private lands.
Science is an iterative process: You start with a question, collect some data to address that question, and, in the process, often end up with more questions. As with all environmental problems, from imperiled species to urban sprawl to global climate change, good information is critical to making intelligent policy decisions. Our three-year study of the Sierra Nevada red fox is the first ecological research ever conducted on this elusive mountain carnivore, and it may well raise a lot of new questions. But our results will shed invaluable light on what steps should be taken to ensure the survival of these beautiful and fascinating animals.
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