Even wildlife conservationists agree: Study proves TNR is the way to go


Sterilize enough community cats (aka stray, feral or free-roaming cats) in a particular area and their numbers will decrease over time. This is so obviously true that it hardly needs repeating (and yet, incredibly enough, a handful of holdouts remains).

In addition to reducing populations at a local level, trap-neuter-return (TNR) programs reduce the number of cats and kittens dying in our communities. Cats who were once rounded up for a one-way trip to the shelter are instead sterilized, vaccinated, ear-tipped and returned to where they were living. Kittens are typically placed for adoption and future litters are prevented.

Again, this isn’t exactly news. But a recently published research paper examining the impact of TNR does shed new light on the subject, providing critical insights that can help us think more deeply about best practices.

Focused and intensive trap-neuter-return efforts

The article, “A Long-Term Lens: Cumulative Impacts of Free-Roaming Cat Management Strategy and Intensity on Preventable Cat Mortalities,” was co-authored by a diverse team of experts in animal welfare, wildlife conservation and veterinary medicine, and published in the open-access peer-reviewed journal Frontiers in Veterinary Science. The authors used sophisticated computer modeling to compare various approaches for managing community cats (e.g., TNR, removal, no action) at low and high levels of intensity.

Among their key findings (nicely illustrated via this “story map”) is the importance of intensity. For TNR efforts to match even modest removal efforts for reducing community cat numbers, at least 75% of the “target population” must be sterilized every six months.

Sounds like a lot of work — and it is. But it’s already being done all across the country.

Success of TNR programs

In fact, such high-intensity, targeted TNR has been an integral part of Best Friends’ community cat programs (CCPs) for years now. By combining this approach with shelter-based return-to-field (RTF) programs, our three-year CCPs produce significant reductions in shelter intake and deaths. We’ve also observed an average reduction of nearly 20% in the intake of kittens under eight weeks of age.

It all makes sense in light of this computer modeling work, which provides a kind of theoretical understanding of the results we’ve seen. And, more important, it allows us to better understand something we’re not seeing: preventable deaths.

We often think of this metric — preventable deaths — in terms of reduced shelter deaths associated with policies and practices (e.g., RTF programs). But it’s easy to under-appreciate the many lives “saved” because they never happened — the direct result of targeted, intensive TNR efforts.

For those of us directly involved with these efforts, it has always seemed pretty intense. I guess that means we’re doing it right.


Julie Castle


Best Friends Animal Society