Wolves are back–barely. After hunting one of the world’s top predators nearly to extinction, the U.S. government is behind their slow recovery under the Endangered Species Act (ESA) and reintroductions that have boosted the population to about 6,500[/url ] in the lower 48 states, [url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1081&context=icwdm_usdanwrc]double its size in 2002.
Yet pressure is mounting again. Western states have re-opened hunting seasons on the species (delisted from the ESA in many states), and some landowners are returning to old methods of trapping, hunting (often from helicopters), and other methods to keep the wolves at low levels.
Swiss biologists are pioneering a new approach by listening to the heart rate of livestock and sounding an alarm (and sending text messages to shepherds) when predators attack. In tests, the researchers attached heart-rate monitors, similar to those used by human runners, to 12 sheep. When two muzzled Czechoslovakian wolf dogs were released near a flock of experimental sheep, the frightened animals’ heart rates soared from 60 beats per minute to 225, triggering the alarm.
The team, including biologist Jean-Marc Landry who authored the paper, Non-Lethal Techniques for Reducing Depredation (PDF), plans to test a more elaborate system next year that will emit a repellent, potentially reducing the need for expensive measures such as guard dogs.
Whether that will change practices in the U.S. is about policy and culture more than technology. Michigan, Minnesota, Wisconsin, and several Western states have removed ESA protections for the species, and are culling the populations. At least 5,000 wolves have been killed legally in the U.S. since the late 1980s, reports the Associated Press in a review of state and federal records.
Yet the total number of cattle killed by all predators each year–several thousand annually–is less than 1% of all deaths. The real culprit, says Montana’s Billings Gazette, are the rigors of weather and life on the range, which killed 22,000 cattle and 52,800 calves in Montana alone.