Most cougar deaths in Alberta study were caused by people

A new study of cougar deaths in west-central Alberta found mortality risk was higher near residential areas and secondary roads and among cougars that frequently crossed human-made clearings. Of the 37 documented cougar deaths, 29 were caused by people.

Hunting was the leading cause of death among the cougars tracked

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Patrick Cummins once had a cougar cross his backyard, climb onto his deck and walk across the roof of his home.

Cummins, who lives near Bergen, Alta., didn't see the cougar. He only saw its tracks in the snow.

In 51 years living on the property, Cummins has never seen a cougar there with his own eyes, though he has caught the elusive predators on trail cameras.

"We always knew there was cougars there," Cummins said. "I suppose we were sort of always looking over our shoulder a little bit, but they've never bothered anybody around here that I know of."

But tracks can make an otherwise invisible predator vulnerable.

A cougar crosses Patrick Cummins's property near Bergen, Alta., on Feb. 7. New research examines how the human footprint affects cougar survival in west-central Alberta. (Submitted by Patrick Cummins)

New research from west-central Alberta suggests roads, homes and other human-made corridors cutting through cougar habitat may affect not only where the animals go, but their chances of survival.

Researchers tracked 80 GPS-collared cougars over five years and found their mortality risk was higher when the animals were closer to homes and secondary roads and when they crossed human-made clearings more frequently.

Of 37 documented deaths, 29 were caused by people.

"I think that's just all about access for hunters, really," said Carter Littlefair, lead author of the study, published Wednesday in PLOS One.

Littlefair, who completed the research while a graduate student at the University of Alberta, said secondary roads can provide hunters with easier access to cougar habitat. Clearings can also reveal where the animals have travelled.

"If a cougar was to cross the road, it's going to leave tracks."

Cougars often avoid trails used by people, which is why the province hopes to reduce trail density in key wildlife areas. (Submitted Delaney Frame/Alberta Environment and Parks)

Human footprint linked to mortality risk

The study followed cougars between 2016 and 2021 across a landscape that included secondary roads and human-made clearings such as seismic lines, powerline corridors and railways.

Hunting was the largest single cause of death, accounting for 16 of the 37. Another eight cougars died after being caught in traps intended for other animals. Five others were killed in vehicle collisions or removals involving problem animals or by a landowner.

Researchers also found a large seasonal difference in survival. Estimated survival was 96 per cent from April through October, but 62 per cent from November through March.

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Alberta's cougar hunting season during the study began Dec. 1 each year and ran through the end of February or until quotas were met.

The research found an association between cougar mortality risk and human-made features, but did not directly measure hunter activity. Littlefair said increased hunter access and the likelihood of detecting cougars could help explain the relationship.

CBC News requested comment from Alberta Forestry and Parks but did not receive a response by publication time.

What the findings mean for the population

Researchers estimated annual survival at about 60 per cent, which Littlefair said is similar to other hunted cougar populations. Hunting also accounted for a smaller share of mortality than in some other studies, he said.

The study did not estimate population size or reproduction, so researchers cannot say whether the population is growing, stable or declining.

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Littlefair said the research provides insight into how cougars die, but cannot determine whether they are dying at an unsustainable rate.

For Cummins, the role people played in the deaths was unexpected.

"Yeah, that surprises me," he said.

"There's more people in the rural areas these days than there used to be," Cummins said. "So from that sense, maybe it's caused by more people being out in the bush."

ABOUT THE AUTHOR

Eric Michael Johnson is a senior writer and editor based in Vancouver. Before joining CBC, he was an award-winning science writer and editor. He holds a PhD in the history of science from the University of British Columbia. He can be reached at eric.johnson@cbc.ca.