Humans are enemies of the environment through destruction and fragmentation of habitat, and cats kill millions of birds. Cats are the #1 pet in Canada & the U.S. Diminished land and suitable nesting areas and predation by feral and outdoor cats have taken a terrible toll on our songbird population which has been in a downward spiral for many years. Please do your part and
keep your cats indoors, and support environment groups that preserve our enviroment, or one of these days it will be as Rachel Carson said "a silent spring".
http://www.fws.gov/birds/mortality-fact-sheet.pdf
http://www.bayjournal.com/article.cfm?article=337
http://wiki.answers.com/Q/What_are_t...pets_in_the_US