It’s no secret Lethbridge is home to hundreds of rattlesnakes, but over the past three decades, urban development has had a massive impact on their habitat, especially on the west side, according to a recent report.
The 2017 Lethbridge Rattlesnake Mitigation report shows the number of rattlesnake relocations have more than quadrupled since last year and the number of deaths in the past decade are at an all-time high.
Between May 2017 and the end of September 2017, 104 rattlesnakes were relocated and 11 were found dead. In 2016, 25 rattlesnakes were relocated and two were found dead.
“I’ve had a few people complain to me that the protection we’re giving the snakes is causing the population to erupt,” ecological consultant Ryan HeavyHead said. “But that’s not accurate. Most of the snakes I picked up this summer were mature snakes so they’ve been around this whole time, they’ve been around four or five-plus years in previous years when we didn’t see this type of activity.”
The report points to several potential factors contributing to the spike, including this season’s prolonged drought, a reduction in the number of prey species and an increase in residents phoning into the city’s emergency hotline.
“There are a lot more people in Lethbridge who are aware of the program now than previously, and who would then be more likely to phone into the hotline when they find a snake, instead of taking matters into their own hands,” HeavyHead said.
But the report also points to added pressure on the rattlesnake population due to urban expansion. According to the report, the large majority of snake-to-human encounters are occurring where large-scale construction is being carried out near their natural habitats.
The Canyons, with its expanding subdivisions and the University of Lethbridge with its Destination Project, are receiving the majority of calls this season.
“The snakes’ habitat, with what little it had remaining, the farmland is now being taken up by development, so they’re looking for places to go,” HeavyHead said. “Out of the 104 relocations of rattlesnakes, I think 68 of them came from that area.”
HeavyHead explained that his predecessor advocated for a migration area to be left untouched between Popson Park and Cottonwood Park, in addition to the areas that were left of the short-grass prairies – about 500 metres above the coulee rim.
“That’s areas where we know is one of the larger hibernacula complexes,” HeavyHead said. “It’s not just one hibernacula, but several hibernaculas of rattlesnakes – that are well-established in that area – that are being affected and some of the development is coming very close to those dens. In some cases, closer than what is mandated by the province in order to protect those snake populations.”
While it’s uncertain whether the number of rattlesnake relocations will continue to increase as rapidly as they did this year, HeavyHead says the data will continue to be analyzed over the winter to help provide more information.