There are few, if any communities in the State of Israel without a resident feral cat population. One can often see store owners and sometimes residents of multi-unit housing complexes putting out a little food for their local cats, who reciprocate by helping to keep down the roach and rodent population.
But the increasing number of free-roaming street cats has become a global problem; in some places stray cats are even considered one of the world’s most invasive species.
However, most people are reluctant to cull their population, as a city would with rat and cockroach populations.
Currently, the most popular population-control method is called TNR, in which cats are Trapped, Neutered and Returned to the same location.
Research led by Professor Eyal Klement and Dr. Idit Gunther of the Koret School of Veterinary Medicine at the Hebrew University of Jerusalem (HU), funded by the Israeli Ministry of Agriculture, investigated the impact of different protocols over a period of 12 years, the first time there has been a controlled study on the subject.
“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 explained.
The findings, which show the importance of implementing a policy of continuously and intensively neutering cats throughout a city, were published in the PNAS journal.
Cats in Rishon Lezion
The study focused on one Israeli city (Rishon LeZion) and tried out different population–control methods over three four-year periods.
In the first, there was no population intervention. In the second, the researchers organized an intensive program of neutering of cats in half of the fifty zones of the city, while the remaining zones served as a control group in which the cats were left without any intervention. In the third period, neutering was applied to the entire cat population of the city.
The study found that neutering in only half of the city zones did not reduce the cat population. The researchers attribute this unexpected finding to the immigration of unneutered cats into the area.
In the third wave, a seven percent annual reduction of cat population was achieved, but a rebound increase in the number of kittens was noted, probably 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,” explained Klement.
The ideal, according to the Israeli study, is to ensure that 70 percent of street cat populations are neutered continuously.
To negate the rebound effect, Klement suggests 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,” Klement said.
Such a measure would ensure cats are fed properly and a policy of neutering could easily be implemented by catching the cats when they come to feed.
