Cats kill 2.4 billion birds and 12 billion mammals every year in US alone29/01/2013 16:09:49 Outdoor cats: Single greatest source of human-caused mortality for birds and mammals, says new study
January 2013. A new peer-reviewed study published 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 in the US alone.
The study, which offers the most comprehensive analysis of information on the issue of outdoor cat predation, was published in the online research journal Nature Communications and is based on a review of 90 previous studies. The study was authored by Dr. Peter Marra and Scott Loss, research scientists at the Smithsonian Conservation Biology Institute and by Tom Will from the U.S. Fish and Wildlife Service's Division of Migratory Birds.
Propblem is even worse than previously suspected
"To maintain the integrity of our ecosystems, we have to conserve the animals that play integral roles in those ecosystems. Every time we lose another bird species or suppress their population numbers, we're altering the very ecosystems that we depend on as humans. This issue clearly needs immediate conservation attention," he said further.
The study's estimate of bird mortality far exceeds any previously estimated U.S. figure for cats. In fact, this magnitude of mortality may exceed all other direct sources of anthropogenic bird and mammal mortality combined. Other bird mortality sources would include collisions with windows, buildings, communication towers, vehicles, and pesticide poisoning.
2.4 billion birds and 12 billion mammals killed by cats
Native species make up the majority of the birds preyed upon by cats. On average, only 33 percent 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 percent 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 behaviours are dictated by animal welfare issues rather than ecological impacts.
Projects to manage free-ranging cats, such as Trap-Neuter-Return (TNR) colonies, are potentially harmful to wildlife populations, but are implemented across the United States without widespread public knowledge, consideration of scientific evidence, or the environmental review processes typically required for actions with harmful environmental consequences."