On a social website, our neighborhood is having a bit of a debate about local "wild" cat populations. In essence, "wild" cat populations consist of both feral and not-feral but not-homed cats in a colony.
The general consensus (during that argument) is that a "Trap, Neuter, Vaccinate, and Return" (TNVR) policy is an effective (and humane) way to control and eventually remove (through attrition) a wild cat population.
Unfortunately, when looking at different materials, they seems to measure cost reduction, or in some cases "stabilization" or the population, but never at the long term success of a TNVR program.
For example:
TNVR has been shown to be the least costly, most efficient and most humane way to stabilize cat populations. from Tampa bay Humane Society
TNVR stands for Trap – Neuter – Vaccinate – Return. TNVR has been shown to be the most humane, most efficient, and least costly method of stabilizing community cat populations. from MEOW Now
Are there any studies or materials that show that TNVR is actually successful at reducing cat populations, ending in the eventual removal of the population from the neighborhood?