In his recent commentary, George Fenwick calls cats "invasive" and "not part of the natural environment," blaming cats for billions of bird and rodent deaths ("The destructive invasive species purring on your lap," Feb. 26). He claims that trap, neuter, return (TNR) programs are a failed strategy and asks for local governments to gather millions of unowned cats and "euthanize" those for which homes cannot be found. Sadly, his claims are not based on facts.
The millions of cats in America are now as much a part of the "natural environment" as are the millions of people on this continent descended from the Pilgrims and other immigrants. Past studies claiming that cats kill hundreds of millions of birds every year have used unscientific methodologies that have yielded grossly exaggerated numbers. Indeed, Britain's Royal Society for the Protection of Birds (RSPB) recently published an article entitled, "Are cats causing bird declines?" The RSPB noted that estimates of how many creatures are killed by cats each year vary significantly. Furthermore, the RSPB stated that "it is likely that most of the birds killed by cats would have died anyway from other causes before the next breeding season, so cats are unlikely to have a major impact on populations."
TNR involves neutering cats and vaccinating them against rabies and other diseases. Since it eliminates breeding and guards against disease, TNR cannot lead to "increased uninoculated populations of cats" as Mr. Fenwick suggests. Finally, local governments have tried for decades to gather and kill unowned cats. But because cats continue to breed, that strategy has failed, whereas TNR has been proven to gradually decrease the free-roaming cat population.
Ron Lambert, Timonium