Sneak a peek at animals using wildlife overpass

Published: November 9, 2020

Drivers hitting Highway 69 north to Sudbury will inevitably find themselves crossing under a large stone overpass near Burwash, Ont., decorated with images of parading moose, bear, and foxes. This overpass is designed for wildlife, not people. Constructed in 2012, it’s part of a multi-pronged approach by the Ontario Ministry of Transport to prevent vehicle collisions with wildlife on the four-lane highway. The strategy includes not just the wildlife overpass but also several wildlife underpasses below the highway, and exclusionary fencing along the road to funnel animals to crossing structures.

 An eight-year long-term monitoring study of the mitigation measures on Highway 69 shows that wildlife such as moose, deer, and lynx have successfully taken to using the crossing structures, and that wildlife-vehicle collisions as reported by the Ontario Provincial Police have declined by 74% following the installation of the wildlife overpass and exclusion fencing along the highway. This promising report shows that providing passageways for wildlife to cross highways helps ensure the safety of both animals and drivers. 

From the driver’s seat, the Burwash wildlife overpass looks like a normal concrete bridge. A bird’s eye view of the overpass shows that the bridge has been planted with shrubs and grasses to create a natural experience for crossing wildlife. 

“What we found in previous studies is that wildlife, especially prey species like moose and deer, are trying to move through a natural environment, not so much through an enclosed dark space,” says Kari Gunson, road ecologist and owner of Eco-Kare International, the consulting company that released the monitoring report.This natural environment can be provided with vegetation. It provides cover for the animals, and it also provides food resources.” 

Eco-Kare International used wildlife monitoring cameras and snow tracks to capture when animals entered and exited wildlife crossing structures. The project was unique in that it covered an eight-year time span. Studies usually only run for five years, maybe two at most, says Gunson, but it can take wildlife some time to warm up to the crossing structures. 

Carnivores like lynx were hesitant at first to use the crossing structures, says Gunson. Ungulates on the other hand, such as deer and moose, used the crossing structures quite soon after construction. The exception was mother ungulates and their calves, who were wary of the Burwash overpass at first. But because the monitoring study ran for many years, over time the researchers observed an increase in mothers and calves travelling across the overpass.

A highlight caught on camera was a sandhill crane family crossing the Burwash overpass. Large mammals are easier to pick up on monitoring cameras, says Gunson, so a family of birds was an interesting surprise. Gunson describes a mother and father with chicks, “walking peacefully,” across the overpass and feeding. “It’s quite interesting to have a diversity of animals,” she says.  

The wildcard species when it comes to highway crossings are black bears. On Highway 69 and other study sites, black bears were able to finagle their way onto roads. The number of wildlife-vehicle collisions as reported by the Ontario Provincial Police following the addition of fencing to the highway showed that while moose and deer accidents declined, collisions with black bears did not.

 “They’re very maneuverable,” says Gunson. “They’re like cats in a way, they can slink down and they can climb. They’ve been able to get through smaller gaps that we might not have thought they can get through.”

Highway 69 is still undergoing twinning south, all the way down to Parry Sound, reminds Gunson. By monitoring the completed section near Burwash, the researchers are now able to put in the lessons learned when installing mitigation methods in the southern region. Additional measures that can be taken to keep bears off roads include burying a mesh apron underneath the exclusionary fencing to seal up any gaps and installing top wires to prevent bears from climbing up and over the fences.

Drivers still need to be cautious when travelling highways and keep their eyes open for wildlife. Fencing isn’t foolproof, and it has to end somewhere. “I would not speed. The slower you go, the more chances you have of being able to stop and react to an animal that’s crossing,” says Gunson. Motorists should also be extra careful in the fall and spring when animals are on the move to and from overwintering sites.

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