Why maintain cat colonies?

Not enough indoor homes …
The number of cats far exceed the number of indoor homes available. The statistics vary widely because un-owned cats are hard to count.  But, animal welfare agencies have reported that there are 5 to 15 cats born for every household in the United States. There are simply not enough indoor homes for every cat.

75 percent of surplus cats come from breeding by stray cats
According to a study done by the National Pet Alliance, 75 percent of surplus cats come from breeding by stray cats. In a presentation to the AHA/CFA Federal Cat Conference in 1996, Karen Johnson of the National Pet Alliance stated that, “Owned cats are not the cause or the solution to the problem of too many cats entering shelters. Unowned cat reproduction must be addressed … by making it as easy as possible for citizens to round up and alter as many stray cats as possible.”

The traditional method of controlling the stray population has been to trap and remove the animals, and then to either place them in homes or euthanize them.  As we see from the numbers mentioned above, placing all homeless cats is not numerically possible; also many stray cats are not tame enough to make suitable pets.

The Cost of Trap / Neuter / Return versus Euthanasia
What about trapping and euthanizing stray cats that cannot be placed? Killing healthy animals is distasteful to most people.  It is also not a solution.  If the cats are removed without changing the environment (i.e.  removing the food source and shelter), more cats quickly replace the cats that were removed.  It is also more expensive to continually trap and euthanize cats than to alter the cats and maintain a colony.  In a study done by the San Francisco SPCA and the National Pet Alliance, they found that the cost to maintain a 1000 cat population using the trap/neuter/return method would cost $17,306 initially and $2,660 a year thereafter.  To trap/remove/euthanize, the cost would be just under $80,000 initially and then just over $60,000 a year after that to keep the population under 1,000.

The Trap / Neuter / Return Method
The trap/neuter/return method has been used in England since the 1960s with much success.  In the United States, the first national organization to be devoted exclusively to the welfare and maintenance of stray cats was formed in 1990, although the method was being practiced on a local level well before then.