When you've studied polar bears for as long as Ian Stirling — nearly 40 years — you become so familiar with your subjects that you sense changes intuitively, before you can find the scientific basis for your discovery. That's what happened in the mid-1990s, when Stirling and his colleagues began to notice declines in the weight and reproductive rates of polar bears on the western coast of Hudson Bay.
“We started to realize,” says Stirling, a senior research scientist with the Canadian Wildlife Service and an adjunct professor of biology at the University of Alberta in Edmonton, “that we were onto something fairly significant.”
That “something” is the effect of the warming climate on the sea ice where polar bears hunt. Earlier ice breakup in the spring is depriving the bears of critical time to prey on seals and fatten up to survive the ice-free months without food. As a result, they weigh about 15 percent less than they did 30 years ago. Between 1987 and 2004, the population in the western Hudson Bay region declined to approximately 950 animals from 1,200, says Stirling, who will share his expertise about the polar predators in April as part of The Royal Canadian Geographical Society speaker series.
Based in part on Stirling's research, the Polar Bear Specialist Group of The World Conservation Union, of which Stirling is a member, recommended in 2005 that polar bears be classified as “vulnerable.” And last December, the United States Fish and Wildlife Service proposed listing the bears as threatened under the Endangered Species Act.
While he grew up in Kimberley, B.C., and spent most of his career tracking polar bears throughout the Arctic, Stirling got his start studying seals in Antarctica as a doctoral student at the University of Canterbury in Christchurch, New Zealand, in the late 1960s. The experience he gained there opened up research opportunities in the Canadian North when he returned to Canada in 1970.
Stirling downplays his accomplishments and adventures as one of the world's leading polar bear researchers, but his work has thrown him into some extraordinary situations. In his 1998 book, Polar Bears, he recounts how he performed artificial respiration for nearly three hours when a bear he had tranquilized stopped breathing, a rare occurrence. (“And just how do you give artificial respiration to a polar bear?” he writes. “Mouth to mouth? Not quite. You lay the bear on its side, take a handful of fur over the rib cage, and lift.”) Then there was the day, in the early 1970s, when Stirling entered a bear den thinking it was unoccupied and came face to face with an adult male — the largest recorded in Canada at the time, weighing 660 kilograms.
Stirling will appear on April 18 and 19 at Ottawa's Centrepointe Theatre.
— Monique Roy-Sole
Posted in Can Geo Talks on Sunday, April 15, 2007