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       A University of Manitoba study published Wednesday in the journal Science Advances is the most comprehensive yet to use the unique circumstances presented by the pandemic to measure what happens to wildlife when human presence is reduced.

       Simon d'Entremont/The Canadian Press

       Birds are just not that into us.

       That’s the inescapable conclusion scientists have reached after combing through millions of bird observations made across North America both before and during the first COVID-19 lockdown last year.

       The results are striking, not just in what it says about the impact of human disturbance on birds, but on the depth of that impact across a wide range of native species, from bald eagles to hummingbirds. Even common birds, such as the American robin – that are widely seen in urban centres and apparently habituated to our presence – had a literal field day during the time that we were stuck inside.

       “About two thirds of the species that we studied changed the way they used the whole continent,” said Nicola Koper, a professor of conservation biology at the University of Manitoba and senior author of new study that looked at the impact of the 2020 lockdown on birds. “It was very obvious that it benefitted a lot of species.”

       The study, published Wednesday in the journal Science Advances, is the most comprehensive yet to use the unique circumstances presented by the pandemic to measure what happens to wildlife when human presence is reduced. Dr. Koper said the results can be used to inform future conservation measures aimed a helping create more useable habitat for birds, at a time when many native species are in decline due to a multitude of pressures.

       Dr. Koper, who specializes in the effects of roads and noise on birds, said she got the idea early on in the pandemic when she had to go out briefly to run an errand in her car and was stunned at the absence of traffic.

       “Before I got to the first light I knew I had to study this,” she said. “It felt immediately like it was going to be a once in a lifetime opportunity – hopefully – to study these questions that I’ve been asking for decades.”

       The challenge was figuring out how to study it. During the pandemic researchers were in lockdown along with everyone else. And while many people anecdotally thought they were seeing more birds while they waited out the lockdown, they also had more time and opportunity to notice them while they waited it out.

       To counter these effects, Dr. Koper and her colleagues turned to eBird, a massive electronic database of bird observations maintained by the Cornell University Lab of Ornithology.

       The database, which continued to accumulated records through the pandemic allowed the Manitoba team to eliminate several factors that might be due to a change in birdwatching behaviour rather than a change in the birds themselves. The team also concentrated on larger urban centres with international airports, where the overall reduction in traffic during lockdowns was expected to be most pronounced.

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       Their analysis encompassed some four million observations of 82 bird species and provided a comparison between what was seen during the pandemic versus the previous three years. To make the comparison, researchers calculated an expected bird count for each species based on how often during an outing an observer would be likely to see a certain kind of bird. A score of 1 would mean the same species was likely to be seen every time, a score of 0.5 meant the species was seen about half the time, and so on. The scores were also compared by distance to roads and airports, which would typically be major sources of noise and disturbance when there is no lockdown in effect.

       The results were dramatic. Many birds clearly shifted their distribution to take advantage of the reduced disturbance, especially species that were in the midst of spring migration during lockdown. A few species were the exception and were seen less frequently near roads when human traffic were low. Dr. Koper noted that one example, the red-tailed hawk – which has a varied diet – may have been responding to the absence of roadkill during the lockdown period.

       Pierre Legagneux, a biodiversity scientist at Laval University in Quebec who was not involved in the study, praised the team for its rigorous methods at extracting a clear signal from the reams of individual bird sightings

       He added that one of the most striking details about the results is how quickly the birds responded to the change. This suggests that future efforts to reduce impacts due to human traffic should yield a similar result.

       “Any conservation method could have immediate impact,” he said.