Richard Gleeson
Northern News Services

Yellowknife ( Jun 12/00) - The tie between predator and prey is no tighter than it is between the lynx and the snowshoe hare.

The hare is the primary prey of the small cats, which populate most of the NWT below the treeline.

Snowshoe hare populations vary dramatically in cycles of 8-11 years. During boom times, you can find as many as 1,500 hares sharing a square kilometre of territory.

Hare populations are expected to approach their peak soon, said Resources, Wildlife and Economic Development biologist Robert Mulders.

"We think the hare numbers are reasonably high across the NWT," said Mulders. "It's possible that next winter, 2001, it might peak. It could be two years, but we're definitely getting up there."

When food is plentiful, lynx flourish. Their reproductive rate increases dramatically. As lynx bounce back from lean periods, kittens can account for as much as 60 per cent of the population.

Recognizing the importance of the relationship, the territorial government has undertaken three long-term studies related to the cyclical changes in population.

A little more than 60 lynx were collared and another 30 kittens ear-tagged and monitored over the last 10 years in a study out of Fort Providence. The study looked at home range size.

It found that during years when there are lots of snowshoe hare, the home range of lynx is 15-25 kilometres. In years of scarcity, lynx use an area two or three times larger to search for more food. Long-range movements of 900 kilometres were also recorded. One animal travelled all the way from Fort Providence to Fort Good Hope.

The government also carries on a carcass collection program, analyzing carcasses brought in by trappers to get an idea of the sex, age and condition of lynx during different stages of the cycle. In the spring, 203 lynx carcasses were sampled.

"One thing we're always keeping tabs on is the number of kits in the harvest. For Fort Providence there was about 21 per cent young."

Hare population peaks and valleys have a profound effect on the survival of newborn lynx.

"There can actually be zero survival in an area (when hare numbers are low). During a peak you can have somewhere in the order of 50-60 per cent of the population comprised of kits."

Lynx pelts destined for fur auctions are also analyzed to determine the age and sex. Counts of snowshoe hare tracks and droppings are also used to track population changes.