Stray cats are considered one of the world’s most invasive species and are responsible for killing large numbers of birds and mammals, while posing a human health risk and carrying disease.
In a controlled study, published in PNAS Journal, Professor Eyal Klement and Dr Idit Gunther at the Koret School of Veterinary Medicine at the Hebrew University of Jerusalem (HU) evaluated the impact of different protocols to manage stray cat populations conducted over a 12-year period. Their findings revealed the effectiveness a policy to continuously and intensively neutering cats throughout a city.
Currently, the most popular population-control method is TNR in which stray cats are trapped, neutered and returned to the same location.
“Although this method has been implemented in various parts of the world, there was controversial evidence regarding its effectiveness for reducing cat populations and no hard evidence regarding its effectiveness in reducing cat-related nuisances or improving their welfare,” Klement says.
The study focused on the Israeli city Rishon LeZion and tested several population control methods over three, four-year time frames. In the first segment, there was no population intervention. In the second, HU researchers organized an intensive cat neutering program in half of the city zones, while the other half served as a control group without any intervention. During the last four years the city’s entire cat population underwent neutering.
Unexpectedly, the study revealed that neutering only half of the city zones didn’t reduce the stray cat population significantly which the researchers attributed unneutered cats entering those areas. A 7 percent annual reduction of cat population was achieved, but a rebound increase in the number of kittens was noted, likely due to an increase in their survival due to lack of competition with the neutered, less aggressive cats.
“Intact cats are more territorial than their neutered counterparts. Once they move into a neighborhood with neutered cats, they tend to thrive and take over,” says Klement.
The ideal control method for stray cats, according to the HU researchers, is to ensure that 70 percent of street cat populations are continuously neutered. To negate the rebound effect, Klement recommends controlling cat food resources in parallel to the TNR campaign.
“This can be achieved by setting up feeding stations in agreed-upon locations and by prohibiting feeding in other public areas,” says Klement. “This would ensure cats are properly fed and a policy of neutering could be implemented easily by catching the cats when they come to feed.”
