Feral cats are thought to be responsible for the extinction of no less than 20 native Australian mammal species, reported Weston Williams in the Australia edition of the Christian Science Monitor. The population density is smaller than the density in North America and Europe, but their impact on the wildlife Down Under is of grave concern.
Australia is not alone. A 2013 study found that cats kill as many as 3.7 billion birds and 20.7 billion small mammals in the U.S. every year.
"All outdoor cats can pose risks to wildlife," said Niamh Quinn, UC Cooperative Extension human-wildlife interactions advisor based at the UC South Coast Research and Extension Center in Irvine. "Keeping cats indoors limits their risk to native species."
According to the story, many conservationists consider cats to be an invasive species and "tough measures" are required protect native animals from their carnivorous habits.
"Currently, trap-neuter-return (TNR) programs are not effective at curbing the population," Quinn said. "Mathematical models of feral cat populations indicate that 71 to 94 percent of a population must be neutered for the populations to decline, assuming there is no immigration . . . Current TNR programs are not operating at this rate."
In Australia, the federal government plans to cull 2 million cats over five years.