This thrush met its end when it crashed into a window, mistaking the reflection of trees for real habitat. Our birds face many threats ranging from collisions and habitat loss to outdoor cat attacks and agriculture-related deaths. Fortunately, we can mitigate some of the risks. Photo by PAUL NICHOLSON.
Many nature enthusiasts have learned that since 1970 bird populations have been in decline. In fact, a recent report from the North American Bird Conservation Initiative, the 2019 State of the Birds Report pegged the drop over the last fifty years at 30%.
This is a shocking change that gets the attention of readers and planners. If we drill down, however, we learn that the threats to our birds can vary depending on the bird family or species. As a result, our responses will be varied. It's not a one-size-fits-all fix that we need. To chart a good path forward, we need to understand the range of threats to our bird populations. Fortunately, some Canadian ornithologists have researched and written on this.
Writing in an issue of Avian Conservation and Ecology, the official publication of the Society of Canadian Ornithologists, Dr. Peter Blancher addressed the predation of wild birds in Canada by house cats and feral cats. In total, cats are estimated to kill at least 100 million birds per year in Canada. Blancher wrote that "even at the low end, predation by house cats is probably the largest human-related source of bird mortality in Canada."
This is a huge annual loss, but at least there is something individuals can do about the problem. There is a super website, catsandbirds.ca, that celebrates the contributions that cats and birds make to our lives. It shows Canadians what they can do to make things safer for both. Keeping cats from roaming and therefore hunting birds freely is one of
the top suggestions.
In another issue of Avian Conservation and Ecology, a team led by Dr. Anna Calvert researched and reported on the relative magnitude of mortality of the many human activities
in Canada that kill wild birds. The team determined that approximately 269 million wild birds and 2 million nests are destroyed each year in Canada as a direct result of human activities, with more than 95% of this loss being the result of cat predation and collisions with windows, vehicles, and transmission lines.
It surprises some to learn that for bird/building collisions, low-rise buildings such as single-family homes present a greater risk than high-rise buildings. This is because birds are more attracted to habitat reflected in the glass than plain blue sky reflections. So again, on an individual basis, steps can be taken. We can retrofit windows by using products such as
FeatherFriendly, DIY tape or films to mitigate the bird/building collision risk. Western University is currently retrofitting at least three buildings' windows with bird-friendly film. ReForest London and other organizations are doing the same.
Calvert's research team did not include in their study indirect threats on birds such as habitat loss, habitat fragmentation, habitat alteration, and site disturbances.
In a 2020 issue of Avian Conservation and Ecology, co-editor Dr. Keith Hobson and Dr. Scott Wilson referenced an International Conservation Fund of Canada report from earlier that year that urged an inter-continental approach to bird conservation. "Population declines of numerous species of Neotropical migrant birds breeding in Canada, including many of the species listed on the Species at Risk Act, are inextricably linked to habitat loss and degradation taking place outside our national borders and especially in tropical forests of Central and South America. A renewed focus on full life-cycle conservation of migrant avifauna breeding in Canada and our international obligations for these species provides a win-win opportunity to both increase our effectiveness in recovering migratory birds in decline, and help fight global biodiversity loss."
Although this is indeed a global issue, we can still take action locally by creating a patch of naturalized habitat if we happen to have a yard. As individuals, we can also participate as citizen scientists by posting bird sightings on eBird Canada and joining in on Christmas Bird Counts, the Great Backyard Bird Count, and similar initiatives.
In yet another issue of Avian Conservation and Ecology, the results of a study of Canadian bird mortality and wind turbines were published. It was determined that on average, each turbine takes out 8.2 birds per year. The Canadian total is much less than cat predation. It is also lower than other collisions such as windows, vehicles, or towers.
Researchers continue to study threats to birds so that we can reduce fatalities and related business costs as well. A study led by scientists from the Cornell Lab of Ornithology in Ithaca, New York about bird/airplane collisions was just published in the Journal of Applied Ecology and it points to opportunities to save time, money, birds' lives, and possibly people's lives.
Bird-Friendly London had produced a "London's Bird-Friendly Skies" pamphlet
that includes a useful summary of ways each of us can help make our city
even more bird-friendly.