Tools That Leave Wildlife Unbothered Widen Research Horizons

You may remember Senator John McCain’s criticism of a study of grizzly bear DNA as wasteful spending. And you may have wondered how the scientists got the DNA from the grizzlies. The answer is hair. The study, which Mr. McCain referred to during his run for president, was a large one, and it provided an estimate of the population of threatened grizzly bears in the Northern Continental Divide Ecosystem, in and around Glacier National Park. The researchers did not trap the bears or shoot them with tranquilizers. Instead, they prepared 100 55-gallon drums with a mixture of whole fish and cattle blood that was allowed to ferment until it had the aroma of grizzly bear candy. They built 2,400 hair corrals — 100 feet of barbed wire around five or six trees — and placed the fish and blood mix in the center. When bears went under the wire to check it out they left hair behind. The team collected 34,000 hair samples in 14 weeks this way. And the population estimate from the study, announced late last year, was 765, a figure 2.5 times the estimate based on sightings of females and cubs, the previously used method. “Hair snaring has given us a much more precise number,” said Katherine C. Kendall, a research ecologist with the United States Geological Survey who designed and implemented the study. The results were just published in The Journal of Wildlife Management. It also gives a glimpse of a growing trend in wildlife biology toward research methods that are gentler — and cheaper — than the classic “capture, mark, recapture.” In that process researchers trap an animal, sometimes drug it and fasten on a radio collar or implant or attach a transmitter. Then they follow the radio signal or catch the animal again to see where it goes...NY Times