Beneath a sunny sky with temperatures hovering near a snake-friendly 50 degrees, Rob Carmichael placed handfuls of 4- to 10-inch long brown and garter snakes into a newly crafted outdoor den at Illinois Beach State Park.
"We hope these snakes will recognize this as their new home," said Carmichael, director of the Lake Forest Wildlife Discovery Center, which hosted them for the last few months in the donated wine chiller.
Their new den is close to the site on the grounds of the decommissioned Zion nuclear power plant, where the snakes were rescued in the dead of winter from a potentially fatal encounter with a railroad work crew.
Grayslake Central High School teacher Chris Kubic discovered the snakes in December hibernating underneath old tracks near the power plant.
Scheduled repair work on the tracks would have disrupted their winter snooze, exposing them to freezing temperatures and possible death.
With snake populations declining in the Chicago area because of the loss of habitat and getting squashed on highways, that wasn't an option, so a special effort was made to save them, said Carmichael.
A small group of snake rescuers teamed up in January with employees for EnergySolutions, the company hired to decommission the plant. The objective was simple: capture as many as they could.
They saved mostly garter and brown snakes along with that lone western fox snake.
Placed in buckets next to warming blanket, the snakes were driven to the wildlife center in Lake Forest and put in the chiller.
First, Carmichael tucked them in boxes filled with a mix of soil and leaves, about 20 to a container. The chiller was set at about 48 degrees, the temperature snakes need to survive in winter.
As spring approached, Carmichael nudged the temperature to 62 degrees to get the reptiles ready for release.
Before the snakes were freed, a new den had to be built, said Brad Semel, a biologist with the Illinois Department of Natural Resources, who helped rescue and release them.
Otherwise, they would have gone back to the old site, a risky proposition considering trains were using the repaired tracks, he said.
EnergySolutions donated railroad ties that were used to help fashion a new nest.
Not all the snakes survived.
"It's the same in the wild — not all hibernating snakes make it to the spring," said Carmichael.
Helping snakes survive is important because there isn't much habitat left in northeastern Illinois to support a large number of them other than at the park and the power plant, Semel said.
"Snakes are a critical component of the ecosystem," he said. "They eat slugs, worms and mice and in turn get eaten by other predators."
The biologists said they will monitor the site. Carmichael has inserted tiny microchips into some of them. Later this summer, they will set up what are called drift fences. The fences periodically stop the snakes, which can then be examined.
The idea is to try to learn whether the rescued snakes are still hanging around.
"It's like a permanent ID, like a microchip you'd put on your pet," Carmichael said.
The discovery of a snake population this large has encouraged Semel and Carmichael to monitor habitat at other places in Illinois Beach State Park.
"You've got rare sand prairie, the shore of Lake Michigan, marshes and open space — all great habitat for snakes," said Carmichael.
Sheryl DeVore is a community producer for TribLocal.