Cats Kill Billions of Birds

Collisions with glass are considered one of the largest sources of anthropogenic mortality in birds, next to habitat loss.
Estimates indicate that up to 1 billion birds in the U.S. and 56 million birds in Canada are killed this way every year.

 
What kills birds?
 

1 October 2013 – Over the last four years, 20 Environment Canada scientists conducted extensive analyses
to produce the first-ever estimates of annual direct bird mortality from human-related sources. Their findings
were published this week in
Avian Conservation and Ecology, the electronic scientific journal
of Bird Studies Canada and the Society of Canadian Ornithologists.

The results indicate that human-related activities destroy roughly 269 million birds and 2 million bird nests in Canada each year.

Most human-related bird deaths (about 99%) are caused by impacts of feral and pet cats, and collisions with transmission lines,
buildings, and vehicles. Cats appear to kill as many birds as all other sources combined – more than 100 million birds annually
in Canada. Species that nest or feed on or near the ground are especially vulnerable to cat predation. Collisions with electricity
transmission and distribution lines have been identified as the second-largest human-caused source of bird mortality in Canada,
causing between 10-41 million bird deaths per year. Collisions with residential and commercial buildings are the third-highest of the human-related sectors, killing an estimated 16-42 million birds each year – mostly at houses.