Jefferson County

Jeffco tagging rattlesnakes

Monitoring program to increase awareness and safety


Less than 100 feet from where a pair of snakes slither under an inconspicuous rock, people stand on belay for their climbing partners on the south face of North Table Mountain.

“This is snake world,” Bryon Shipley said.

Shipley with his two orange buckets seemed to go unnoticed by hikers, climbers and others on North Table on a recent Saturday afternoon.

When he took the buckets out of his truck earlier in the day, a colleague quipped that it sounded like the buckets were “leaking air,” thanks to the tail flicking from rattlesnakes.

Shipley works for Adaptative Environmental Services is a company that specializes in land and wildlife conservation, management and research that Jeffco Open Spaces has contracted with to round up 20 rattlesnakes on Golden’s North Table Mountain, implant tracking devices and release them.

“This is primarily a visitor safety and awareness concern,” said Andrew DuBois, education specialist for Jeffco Open Spaces who is coordinating efforts with Adaptive Environmental Services.

North Table is heavily used by climbers, bicyclists, trail runners and hikers. The data the snakes give will help with public education and future planning, DuBois said. Knowing where a rattlesnake den is located would help with future planning and development like putting in new trails — and avoiding putting them atop of snake den.

The goal is to collect 20 snakes — four from each quadrant of the mountain — and track their travel habits to identify potential den sites and frequently visited areas.

Wrangling snakes

By April 28, the team had collected five rattlesnakes. But some snake hunting days are better than others. On May 5, they found just one. The next day they had caught and released three snakes by noon.

Morning is the best time to look for rattlesnakes, Shipley said. They hunt at night, find a place to curl up when it gets too cold then in the morning bask in the sun to warm up and digest their food from the night before. However, rattlesnakes heat up quickly, thus often prefer some shade alongside their sun spot. Even just poking their head out from a hole for sunlight can transfer the warmth to the rest of the body, he explained.

But as the temperature increased into the 80s on May 6, the likelihood of finding rattlesnakes decreased.

“They live underground most of the time,” Shipley said.

Team members crept slowly along rocks, looking under overhangs and into crevices.

Oftentimes, people can walk past a rattlesnake just a foot or two away and never know it, Shipley said. Their skin is a natural camouflage and they’d rather not have a confrontation, so they lay still and wait for people to pass if they don’t think they’ll be a threat.

Shipley said he has walked past a rattlesnake while looking for them and didn’t realize it until someone else pointed out the serpent.

The conditions on North Table are ideal for rattlesnakes, there are plenty of mice to forage for, rocks to hide under and sun to lay in.


The research team is implanting a four-gram microchip in the snakes it finds, not too unlike what might be in a cat or dog to help identify them. However, these chips are for tracking location. The range is only about 100 feet, depending on what obstructions there may be. Shipley said he doesn’t anticipate the rattlesnakes to migrate off the mountain.

“The ideal situation is to represent the population,” DuBois said.

DuBois said it’s difficult to get a figure of how many rattlesnakes probably live on North Table without a more in-depth study, however, they have to balance scientific value with funds available so hope 20 snakes will be enough to get an idea of habits and den sites.

“They are remarkably resilient animals,” Shipley explained. “They’re faced with a lot alterations in their habitat, but they seem to be able to respond to that pretty well if given the chance.”

Spotting a snake

There are 32 species of snake in Colorado and only three are venomous: the desert massasauga, prairie rattlesnake and faded rattlesnakes, according to Shipley. The prairie rattlesnake lives on North Table. The other two aforementioned live elsewhere in Colorado. Shipley said they’re usually reclusive.

Rattlesnakes are often confused with bull snakes, he said, because of the color pattern. However, that’s about all they have in common. The non-venomous bull snake is constantly on the move seeking out prey while the rattlesnake prefers to patiently wait for a meal to come walking by. And the hotter it gets outside, the more the rattlesnake prefers to be nocturnal. The non-venomous racer snake is also very common on North Table.

People can keep up with the progress of snake collecting and research through Shipley’s blog at

North Table Mountain, #NTM, rattlesnakes, jeffco open space, hiking, biking, dogs, trails


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