Feral cats fail to fulfil their role as rat controllers in New York City, new research reveals.

Cats (Felis catus) are often released in New York in the belief that they will make a dent on the city’s centuries-old rat problem. However, a study of the two species in the mean streets of Gotham reviewed 306 videos of cat-rat interactions over a 79-day period and found that just two – yes, two – rodents lost their lives.

In contrast, earlier research from the US suggests that feral cats are likely the single greatest source of anthropogenic mortality for US birds and mammals. In Australia, a 2017 review on cat predation on birds estimated that they consume up to a million native birds per day.

The latest study, from a team led by Michael Parsons of Fordham University in the US, acknowledges that cats are clearly efficient killers, but concludes that the low rat kill rate over nearly three months suggests they are avoiding them and opting for less challenging prey.

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BIOLOGY

New York rats are brown rats (Rattus norvegicus) and famed for their size and fearlessness. Online videos abound of subway rats crawling on sleeping commuters, or stealing slices of pizza.

“New Yorkers often boast their rats ‘aren’t afraid of anything’ and are the ‘size of a cat’,” says Parsons. “Yet cats are commonly released to control this relatively large, defensive and potentially dangerous prey.”

Parsons’ team – which included US and Australian biologists, as well as a professional pest exterminator – suggests that the practice of releasing cats to control rats has a deleterious effect on smaller creatures of the urban ecosystem. Brown rats weigh on average 330 grams, in contrast to a typical 15-gram bird or 30-gram mouse…..more here