When COVID rules kept humans home, wildlife roamed more freely, international study shows

When the COVID-19 pandemic forced humans to hunker down at home, wild animals took advantage of our absence, new research shows.

The study, authored by 175 researchers from around the world, examines how pandemic restrictions during the height of the global health crisis altered animal behaviour.

Researchers found that when human mobility was constrained by lockdown measures, wildlife soon took notice — moving closer to roads and moving more freely across the landscape. 

From elephants in Botswana to grizzlies roaming the Rockies, animals enjoyed the solitude when places became largely devoid of people.

"One of the biggest surprises was actually seeing animals respond and change their behaviour in such a short time," said Marlee Tucker, an ecologist at Radboud University in the Netherlands and the study's lead author.

The study, published this month in the journal Science, examined 43 species of terrestrial mammals, relying on data gathered from 2,300 individual animals fitted with radio collars or other GPS trackers.

Giving wildlife the space to remain wild can have an immediate impact on their movements, the study found. The findings may help inform future conservation efforts, Tucker said.

"This is quite a positive, optimistic finding because it shows that animals still retain this capacity to alter their behaviour," Tucker said.

"It suggests that maybe making small changes in our behaviour could actually reduce our impact." 

Researchers monitored changes in animal behaviour during the spring of 2020 compared with the same time period in the year before. Each data set was assigned a "lockdown start date" based on national government regulations at the time. 

Three trends emerged. 

When they were tracked over 10-day time spans, animals travelled on average 73 per cent farther as they migrated, hunted and foraged food.

Roadkill numbers were reduced even as animals moved 36 per cent closer to roads in densely populated areas. 

When tracked over short, one-hour time spans, animals in densely populated areas moved less — likely because humans weren't around to scare them off.

This bolder behaviour was seen across species, the study found.

Mountain lions in California moved closer to the edges of cities than they did before the restrictions. Crested porcupines — found in Italy, North Africa, and sub-Saharan Africa — began proliferating in urban areas. Invasive eastern cottontails began hopping about more during the day.

An accidental experiment 

Tucker said the pandemic produced the right variables for an unexpected natural experiment.

When the pandemic was declared and people began swapping stories of wild animals taking to city streets amid lockdowns, she began making calls to her counterparts around the world.

"We realized this was a very unique opportunity where human activity was drastically altered.

"Our behaviour changed almost overnight in many counties," she said, noting that further research into the impact of the pandemic on wildlife movements is ongoing across the globe. 

"This was one very rare occasion where we could separate human behaviour from changes on the landscape." 

Animals were tracked for an average of 59 days. The study notes some outliers in the data as some species reacted differently to the absence of humans.

For example, mountain lions explored more in urban areas when restrictions were tight, while species such as American black bears, bobcats and coyotes roaming within the same habitat did not. 

Many iconic Canadian species, including wolves, black bears and Rocky Mountain bighorn sheep, were reflected in the study. 

Mark Hebblewhite, an assistant professor of wildlife biology at the University of Montana, said biologists involved in monitoring wildfire movements saw the pandemic as an opportunity to collaborate.

Hebblewhite, who studies elk in the Alberta Rockies, said many of the study authors had worked together on a 2018 paper examining how human activity in general altered wildlife movements.

"It was serendipitous, an accidental experiment," Hebblewhite said. "As COVID came, we saw some of the biggest and most novel ways that human behaviour has changed in probably 100 years." 

He said researchers involved with GPS studies often lean on each other for guidance, noting that biologists from B.C., Alberta and Parks Canada were among the study's contributors.

"You can imagine the GPS data you get from an elk isn't actually that different from the GPS data you get from a radio-collared raccoon in terms of how you analyze it, so that is how we got connected with this global network of people." 

For more than two decades, Hebblewhite has been tracking populations of free-roaming elk at Ya Ha Tinda Ranch in Banff National Park, a historic property that serves as home range to one of Alberta's most ecologically important elk herds.

He said the isolated ranch acted as a control site for the study, as there are few visitors. In contrast, the impacts of COVID regulations were much more pronounced in places like Alberta's Bow Valley, a scenic mountain destination popular with visitors, he said.

Despite the variations in the results, Hebblewhite said the research confirms that wildlife can benefit from conservation practices that keep humans at bay, even for a short time.

For example, temporarily closing a park or road to give sensitive species adequate space to complete their annual migrations can provide valuable protection.

"Wildlife spend a lot of their time avoiding human activity," he said. 

"During COVID, when humans were locked in their homes, wildlife could relax a lot … they had free rein."