Despite his twenty year's experience trapping lynx, British Columbia trapper Paul Blackwell remains mystified by their behavior.

"They'll walk by a cubby three or four days in a row then suddenly decide to go in and get trapped," he said. "It doesn't make any sense to me." After a week of trapping, Blackwell and his six fellow trappers have only two lynx in the holding pens to show for their efforts ... yet Blackwell has caught as many as four in one day.

A cubby is a trap site, usually covered by tree limbs and brush, which holds the bait, usually a dead snowshoe hare. The padded, leghold traps are placed a step or two in front of the hare so as the lynx walks up to investigate, it is caught. Trappers usually swab the hare with a "lure," a concoction of ingredients that can include anything from catnip to Chanel No.5 perfume.

So far this season, Blackwell has yet to come up with the right mix. "Usually they can't seem to resist Chanel No.5," Blackwell says with a grin. "But this year nothing seems to work just yet. A fellow trapper just gave me some stuff consisting of lynx urine, feces and other secret ingredients he wouldn't reveal! We'll give it a go for the next few days."

Part of the problem, he surmises, is that the snowshoe hare population is approaching the peak of its nine to 11-year cycle, and there is too much food available for the lynx to be hungry enough to go into the cubbies. It is a dilemma since the lynx population, which follows the hare population, is also reaching a peak.

"We've got lynx all over the place, but I think they're just too satisfied to be interested in the hares we've placed in the cubbies," he laments.

The lynx/snowshoe hare cycle is one of the most documented relationships in the biological world. Records from the Hudson's Bay Company going back to the mid-1800s have demonstrated snowshoe hares go through a boom/bust population cycle that runs from about nine to 11 years. The population builds, then suddenly crashes. The lynx, which depend almost solely on the hares, follow the same cycle, about a year behind.

Blackwell reports that at the height of the cycle, he has counted as many as 50 hares in an hour. The following year, he may only count one in the same area. British Columbia biologists report that the lynx population can jump from a low of two per forty square miles to sixteen in the same area at the peak of the cycle.

"You find the hares infested with ticks and other parasites ... many just seem to starve to death," he said. He added that there is some evidence the bushes hares feed on actually turn toxic when they are overgrazed, possibly a botanical mechanism that allows the plants to recover before they are overgrazed to the point of being killed.

Once the hare population crashes, the crash of the lynx population follows. Unlike other carnivores that will switch to hunting other species, the lynx in Canada does not adapt to the loss of the hares. Blackwell says that bobcats, for instance, have been known to catch deer during a downturn in rodent populations but he's never found any evidence of lynx, virtually identical in size to bobcats, doing the same. Apparently many simply starve to death.

"Oh, I'm sure if a grouse or a squirrel jumped up in front of them, they'd take it," Blackwell says, "But they are so tied to the hare as their prey species, they just don't seem to be able to adjust."

Nevertheless, it is a relationship that has successfully developed over tens of thousands of years and there is no reason to think it won't persist, given the adequate protection of the habitat needed for both species to prosper.

December 17, 1998
After 20 Years, Trapper Still Mystified by Lynx Behaviour