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Number of birds killed each year by human-related activities estimated by Environment Canada scientists


Yellow warbler sitting on nest © iStockphoto
Yellow warbler sitting on nest © iStockphoto

Although Canada is home to billions of birds, many species are showing population declines as a result of stresses to our ecosystems (see The State of Canada’s Birds, 2012). Widespread loss and fragmentation of habitat has increased the number of interactions between birds and human activities. To better understand and address the resulting impacts, Environment Canada scientists undertook a series of innovative studies to estimate the number of birds and nests inadvertently destroyed annually within Canada, as a result of a range of human activities.

These scientific results have been published in a special issue of the Canadian electronic scientific journal Avian Conservation and Ecology. The issue includes nine sector-specific articles together with a synthesis report considering the overall effects of these mortality sources. 

Environment Canada estimates that over 276 million birds and 2 million nests are destroyed annually across Canada, and the results show: 

  • Cat predation and collisions with windows, vehicles and power lines kill the most birds
  • Localized sources of mortality, such as fisheries bycatch, can have important species-level impacts
  • Management practices aimed at reducing widespread and important localised effects can greatly reduce bird mortality, and support bird conservation across Canada

Maintaining healthy bird populations in Canada will require managing mortality from human-related activities within the context of long-term effects of habitat loss, and mortality resulting from natural sources, such as predation, disease and severe weather. These estimates provide a positive first step in understanding the relative importance of different causes of mortality for our bird populations and will help focus the conservation actions of Environment Canada and its partners. 

Contacts: Dr. Elsie Krebs, (604) 350-1990,, Wildlife and Landscape Science Directorate; and Silke Neve, (819) 938-3911,, Canadian Wildlife Service

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