Biologist Francis Iredale pressed his hand against a boulder in the Batchelor Hills, trying to get a reading of a largely invisible form of life.

His interest wasn't in the boulder itself, of course, but in what it might conceal — a western rattlesnake.

Rattler dens are found in and around the south-facing rock outcrops. As the rock warms at this time of year, the reptiles slither out for some cool time.

"You can really see why it's important to protect these denning areas," said Iredale, who works for the Ministry of Forests, Lands and Natural Resource Operations.

Kamloops subdivisions, particularly those in Brocklehurst and Westsyde, encroach on critical habitat for the blue-listed crotalus oreganos, a venomous pitviper species. Species habitat in B.C. is limited, often located where development occurs, which is why populations are struggling. Having a low reproduction rate — females reproduce only once every two to three years — doesn't help, either.

"It's a threatened species, so we just have to work with everyone to recover the population. It's really a unique species for this area. It's a good, core grouping."

This summer, with $26,000 provided by the Habitat Conservation Trust Fund, Iredale is co-ordinating a habitat mitigation project in the Batchelor Hills. It's a continuation of a pilot project three years ago that had snake-proof fencing erected around portions of Batchelor neighbourhoods.

The new funding will pay for additional fencing to close gaps as well as for a public awareness program. Students will be going door to door this summer to educate residents on how to keep the snakes out of their yards and protect the population.

The mesh fence, combined with additional screening embedded in the ground, has helped to reduce human/snake encounters.

"They really don't want anything to do with people," Iredale said. Encounters are few and the snakes generally give plenty of warning with their characteristic rattle.

"It's very rare to have that occur, and that speaks to the snake's behaviour as well." They're typically docile creatures, contrary to the prevailing myth about snakes as a threat to humans. Most often, it's the other way around.

As many as 200 rattlers dwell in the vicinity, but their number doesn't make them any easier to locate, even on a day when they're drawn "outdoors." That was the case on Friday, when a half-hour search through the hills led to little more than litter and sagebrush.

The rattlers were there, no doubt, just invisible.

Iredale said the project, in partnership with the City, serves as an example to other municipalities that are home to rattlers.

"The City, seeing how effective this was, made a requirement for new subdivisions to have snake fencing installed automatically."