Tuesday, October 1, 2013

Running the gauntlet--Environment Canada study shows 269 million birds killed each year in Canada

The endangered Loggerhead Shrike is affected by habitat loss and perhaps pesticides but today's study listed more immediate causes of death, such as collisions with vehicles, buildings, power lines, and predation by cats

Today a study by Environment Canada (Birdlife International summary here) in Avian Conservation & Ecology released estimates of the number of birds killed in Canada by human-related activities. Assimilating data from a variety of bird research sources,  the scientists determined that we are killing roughly 269 million birds and destroying 2 million bird nests in Canada each year.

That is nearly 5% of the estimated total number of birds we have in Canada during a given year.

And that does not include the loss of birds from habitat destruction--undoubtedly a more serious concern but one that is harder to quantify. The report does, however, estimate that between 1200 and 5,200 nests are destroyed as forests are felled for tar sands each year. Less direct causes of bird decline related to oil and gas exploration and other industrial activity are not included in the study.

Birds that breed in farm land such as this Brewer's Blackbird and this Swainson's hawk are vulnerable to pesticides, electrical transmission lines, and collisions with vehicles
Perhaps most alarming to some will be the figures on the numbers of birds killed by cats. Studies in other countries have made it clear that our cats are killing more native birds than any other single direct cause of anthropogenic (human related) mortality. This new Canadian study confirms what has been proven in the U.S. Cats are NOT native to any North American ecosystem and both pets and feral animals receive a boost in their predator efficacy by being fed and sheltered by people.

Tomorrow (October 2)on CBC Blue Sky at noon I will be with Garth Materie discussing the new report and what Canadian individuals and communities can do to help. Though habitat loss and degradation (serious but more indirect causes of long term bird decline) are beyond the scope of the study, it is worth seeing what we can do to limit causes that are in some ways more easily addressed. Everyone can control their cats, bylaws can be passed and enforced to control cat populations and shut off lights in highrises, and our buildings and electrical transmission lines could be designed to reduce bird mortality.

between 76 million and 416 million birds like this Northern Waterthrush are killed by cats in Canada each year



Nature Canada has responded to the report by calling on all levels of government and Canadian citizens to take some simple measures:
  • neuter your cats
  • keep them indoors, especially at dawn and dusk and especially during the peak migration periods of April 10 to June 1 and August 15 to October 15.
  • enforce bylaws that control stray cat populations. Neutering them is not enough--more than 60% of the birds cats kill are taken by the 25% of cats that are feral.
  • Civic governments need to look at building design standards to protect bird mortality from collisions with windows and building lit up needlessly at night.
  • Both Federal and Provincial governments need to consider bird mortality when doing the environmental assessments for any new energy projects and transmission lines (in Saskatchewan right now SaskPower is designing a major transmission line directly across the continent's primary Whooping Crane flyway. Collisions with electrical lines is the number one cause of Whooping Crane mortality in migration. All to serve the potash industry which should be helping to reduce the risks.)

    This lovely creature, the Black-necked Stilt deserves some legislation 
    and regulation to reduce all of the direct and indirect 
    causes of mortality--including the habitat loss that is not 
    discussed in the Environment Canada report.

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