A while back I ran a post on a really silly article in The Age defending the role of feral cats in the environment arguing that negative attitudes toward them were analogous to racism towards migrants. The facts are that cats are among the most destructive element in our local environment.
This claim is verified in a recent US study. A peer-reviewed study published today and authored by scientists from two of the world’s leading science and wildlife organizations – the Smithsonian Conservation Biology Institute and the U.S. Fish and Wildlife Service (FWS) – has found that bird and mammal mortality caused by outdoor cats is much higher than has been widely reported, with annual bird mortality now estimated to be 1.4 to 3.7 billion and mammal mortality likely 6.9 – 20.7 billion individuals. As one of the authors states:
“The very high credibility of this study should finally put to rest the misguided notions that outdoor cats represent some harmless, new component to the natural environment. The carnage that outdoor cats inflict is staggering and can no longer be ignored or dismissed. This is a wake-up call for cat owners and communities to get serious about this problem before even more ecological damage occurs”.
The median number of birds killed by cats annually is 2.4 billion and the median number of mammals killed is 12.3 billion. About 69% of the bird mortality from cat predation and 89% of the mammal mortality was from un-owned cats. Un-owned cats are defined to include farm/barn cats, strays that are fed but not granted access to human habitations, cats in subsidized colonies, and cats that are completely feral.
Free-ranging cats on islands have caused or contributed to 33 (14%) of the modern bird, mammal, and reptile extinctions recorded by the International Union for Conservation of Nature Red List of threatened animals and plant species.
Native species make up the majority of the birds preyed upon by cats. On average, only 33% of bird prey items identified to species were non-native species in 10 studies. Studies of mammals in suburban and rural areas found that 75–100% of mammalian prey were native mice, shrews, voles, squirrels, and rabbits, all of which serve as food sources for birds of prey such as hawks, owls, and eagles.
The study charges that, “Despite these harmful effects, policies for management of free-ranging cat populations and regulation of pet ownership behaviors are dictated by animal welfare issues rather than ecological impacts”. (my bold)
This is denying precisely the view of the foolish Age article. To be clear I have no antagonism towards cats and agree that these faithless creatures give pet owners much pleasure. But I believe that feral and free-ranging cats should be destroyed and that cat ownership should be absolutely denied to those living within a few kilometres of parks and wildlife reserves. (1121)