Study: Cats named the leading cause of bird deaths in Canada
theweathernetwork.com
Tuesday, October 1, 2013, 8:56 PM -
Environment Canada has released a report on the top causes of bird deaths in Canada, and it's not looking good for our feline friends.
Feral and domestic cats have been named the top cause of bird deaths across the country, claiming more than 133 million lives annually.
The paper concludes that approximately 269 million of the country's 10 billion birds are destroyed by human activity each year.
That's the equivalent of 186 million breeding individuals.
When combined, "cat predation, and collisions with windows, vehicles and transmission lines caused >95% of all [avian] mortality," the study's authors write.
The data was compiled from various studies as well as publicly-available information, like national housing statistics and the number of cats in Canada.
Because there haven't been many studies on bird mortality rates, there is some uncertainty with the estimates. Still, researchers say the paper sheds a light on the impact human activity can have wildlife populations.
"Some sources of human-related avian mortality are well-quantified, such as the regulated sport harvest of game birds, but the magnitudes of most sources are precise or unknown," the authors write.
"In particular, those affecting a few birds at a time, e.g., a cat predation or building collisions, may often be overlooked because their local effects are extrapolated nationally."
Top ten causes of human-related avian mortality in Canada
| Source | Approximate number of annual bird deaths (of 186 million breeding individuals) |
| 1. Cats (domestic and feral) | 133.5 million |
| 2. Transmission line collisions | 16.8 million |
| 3. Houses | 16.4 million |
| 4. Road vehicle collisons | 9.8 million |
| 5. Pesticides | 2 million |
| 6. Harvest (migratory game birds) | 1.8 million |
| 7. Low and mid-rise buildings | 1.3 million |
| 8. Harvest (non-migratory game birds) | 1 million |
| 9. Commercial forestry | 887,835 |
| 10. Chronic ship-source oil | 282,700 |
Source: Environment Canada
Preventing window collisions
Some collisions are unavoidable. Researchers at the University of Alberta believe many avian window fatalities are caused by "panic flight", a phenomenon that occurs when a bird is caught off-guard.
Still, there are a number of ways homeowners can reduce risks:
- Keep bird feeders within three feet of a window. That way, birds won't be able to gain enough speed to seriously injure themselves, should they come into contact with a window
- Hang an ornament. A simple sun catcher is enough to let a bird know that they're about to fly into a wall.
- Add stickers or decals to your windows. Experts recommend keeping decals close together -- about a hand's width apart. Images that resemble hawks or raptors are sure to steer small birds away from windows.
- Keep plants away from windows. If this isn't possible, consider installing a protective mesh screen. There are a variety of companies that perform this service at a reasonable cost.
- Keep your blinds drawn or install frosted windows. While blinds can help, they're rendered ineffective when placed against a reflective window. Many hardware stores sell opaque films that can be easily applied.
Cats: The not-so-silent killer (courtesy: Wikimedia Commons)
