When communities struggle with free-roaming cats, two approaches are often considered:

Trap-and-Kill (impound and euthanize)
Trap-Neuter-Return (TNR) or Return-to-Field (RTF)

While trap-and-kill may sound like a “quick fix,” decades of evidence shows it doesn’t work. Cats reproduce quickly, new cats move in to take the place of those removed, and the cycle begins again. TNR, on the other hand, provides lasting population reduction, saves taxpayer dollars, and is a humane and effective solution.

Below are key statistics from scientific studies and municipal programs across the United States and beyond.

The Failure of Trap-and-Kill

Mathematical models show that to shrink a cat population through lethal removal, more than 50% of the cats must be removed every single year—an unrealistic, costly, and unsustainable threshold (Andersen, Martin & Roemer, JAVMA 2004). Another model demonstrated that unless extremely high levels of removal are maintained, populations quickly rebound through reproduction and immigration (McCarthy, Levine & Reed, PLoS ONE 2013).

In practice, this means trap-and-kill drains resources but fails to deliver long-term results.

The Success of Trap-Neuter-Return

San Jose, California

When the city shelter replaced routine euthanasia with Shelter-Neuter-Return, cat and kitten impounds fell by ~29%, and euthanasia dropped from over 70% of intakes in 2009 to just 23% in 2014 (Johnson & Cicirelli, PeerJ 2014).

Louisville, Kentucky

An eight-year Return-to-Field program combined with targeted TNR produced dramatic improvements: 94% reduction in feline euthanasia and a 43% drop in intake (Spehar & Wolf, Animals 2020).

Albuquerque, New Mexico

A citywide integrated program of RTF and TNR resulted in sustained decreases in euthanasia and intake at the municipal shelter (Spehar & Wolf, Animals 2018).

Alachua County, Florida

High-intensity, zip-code-targeted TNR reduced shelter intake and euthanasia substantially more than in non-target areas still relying on conventional impound/euthanize (Levy, Isaza & Scott, Veterinary Journal 2014).

University of Central Florida (Campus Study)

Over 11 years, TNR combined with adoption led to a long-term population decline and the complete cessation of kitten births (Levy, Gale & Gale, JAVMA 2003).

Newburyport, Massachusetts

After 17 years of community-wide TNR, the waterfront colony declined from ~300 cats to zero. Earlier attempts at lethal control had failed, but sterilization and adoption solved the problem (Spehar & Wolf, Animals 2017).

Rome, Italy

A city-managed sterilization program significantly reduced colony sizes and kitten births, proving effectiveness even on a large, urban scale (Natoli et al., J Feline Med Surg 2006).

Cost Effectiveness

Trap-and-kill is not only ineffective—it’s expensive. Taxpayer dollars go toward catching, housing, and euthanizing cats year after year with no permanent reduction. In contrast, TNR stabilizes colonies, stops the birth of new litters, and reduces shelter intake. That means fewer taxpayer dollars spent on intake and euthanasia over time.

San Jose and Louisville are prime examples: both saw sharp, sustained drops in intake and euthanasia once TNR/RTF replaced trap-and-kill, lowering costs while improving community outcomes (Johnson & Cicirelli, PeerJ 2014; Spehar & Wolf, Animals 2020).

The Takeaway

Communities across the U.S. and abroad have tried both approaches. The evidence is clear:

Trap-and-Kill = Costly and Ineffective
Trap-Neuter-Return = Humane, Cost Effective, and Proven to Work

For borough councils, township supervisors, and community leaders, supporting TNR is not just the compassionate choice—it is the practical, fiscally responsible one.

The bottom line, most trappers and residents will not help trap if they know the cats will be euthanized.

That’s why organizations like PennyFix are critical—by funding spay/neuter efforts through innovative solutions like a penny-per-can surcharge and donor support, PennyFix helps make humane programs like TNR possible in communities that need it most. But PennyFix can’t do it alone—without sustained funding, even the best solutions falter. It’s in the best interest of local governments to support spay/neuter organizations like PennyFix instead of relying on costly, ineffective trap-and-kill approaches.

TNR vs Trap-and-Kill