section_path: Ecology/Impact on wildlife
section_name: Impact on wildlife
paragraph_text: Impact on wildlife
  
  On islands, birds can contribute as much as 60% of a cat's diet. In nearly all cases, the cat cannot be identified as the sole cause for reducing the numbers of island birds, and in some instances, eradication of cats has caused a " mesopredator release " effect; where the suppression of top carnivores creates an abundance of smaller predators that cause a severe decline in their shared prey. Domestic cats are a contributing factor to the decline of many species, a factor that has ultimately led, in some cases, to extinction. The South Island piopio, Chatham rail, and the New Zealand merganser are a few from a long list, with the most extreme case being the flightless Lyall's wren, which was driven to extinction only a few years after its discovery. One feral cat in New Zealand killed 102 New Zealand lesser short-tailed bats in seven days. In the United States, feral and free-ranging domestic cats kill an estimated 6.3–22.3 billion mammals annually.
  
  In Australia, one study found feral cats to kill 466 million reptiles per year. More than 258 reptile species were identified as being predated by cats. Cats have contributed to the extinction of the Navassa curly-tailed lizard and Chioninia coctei.