In Polar Bear Territory - 05-20-2011, 04:54 AM
By KATE STAFFORD Kate StaffordA mother and two cubs traverse the lead on a thin layer of new ice.
Kate Stafford, an oceanographer at the Applied Physics Laboratory at the University of Washington, writes from Alaska, where she is participating in a visual census of bowhead whales.
Kate StaffordA polar bear that wandered to within 400 meters of the perch.
We have been seeing a lot of polar bears lately. The first three weeks I was up here, I saw three. One was napping on a large ice floe that was being pushed south by the current. The other two were off an abandoned trail deep into the ice. The best evidence of bear presence was the tramping down of our trail markers; nature may abhor a vacuum, but polar bears canít stand survey flags.
In the past few days, seeing bears from the perch has been a common occurrence, and during some watches the number of bears sighted has surpassed that of whales. Everyone stays alert while traveling to and from the perch to prevent any unexpected encounters with bears. The lead has been open, but weíve had low winds and currents, so new ice has formed over much of the previously open water. This new ice provides good resting habitat for ringed seals (a preferred food of polar bears) and is a bridge of sorts by which bears can pass from the pack ice to the fast ice in search of food.
Kate StaffordA mother bear nursing her two cubs.
While these frequent visitors have caused us to increase vigilance while on watch, they have also provided a rare opportunity (for most of us) to observe polar bears in the wild. Many of the bears pass by the perch on their way somewhere else, usually along the lead edge. Some decide to nap nearby and drape themselves over a convenient chunk of ice. A female with two older cubs spent an hour or two on the new ice in front of the perch chasing, eating and playing with eiders that were sitting in nearby ponds of open water. A few days later another female, with smaller cubs, nursed them out on the edge of the new ice. We had one bear pass by the perch twice in just over an hour, both times heading south. Just when and where did he circle back? It is such a privilege to watch these large predators go about their day in their natural habitat, and it is impossible not to consider that this habitat is changing, rapidly, and wonder how well they will adapt to these changes.
Kate StaffordJason Herreman collecting a polar bear hair sample.
Jason Herreman, a biologist at the North Slope Borough Department of Wildlife Management who helps run the whale census, is also looking at polar bearsí use of bone piles north of Barrow, a project that involves collecting small hair samples on a snare set up near areas used frequently by bears. Genetic material from the hair (which is snagged painlessly on barbed wire) can be used to look at how many bears rely on bone piles, what time of year the activity occurs, and whether the same individuals return again and again. It also provides the genetic identification of individuals to include in future population estimates of bears using capture-recapture methods similar to the photo identification project for bowhead whales.
Jason HerremanPolar bears photographed with a motion-sensor camera.
In addition to the hair snare, Jason has a motion-sensor camera set up at the site to photograph the animals and help monitor the effectiveness of the snare. This project is a collaboration between the North Slope Borough and the United States Geological Survey in an effort to use noninvasive techniques to monitor polar bear populations. There are plans to expand this project to other areas.
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