Stray and feral cats are a problem we in rescue have faced for some time now.  If left unaddressed the problem can quickly balloon out of control. A pair of breeding cats, which can have two or more litters per year, can exponentially produce 420,000 offspring over a seven-year period. 

Cats left on their own form colonies.  These colonies usually consist mostly of feral cats.  Feral cats are wild cats that can be very dangous to humans.  The most effective way of dealing with this issue is trap and release.  Its a way to control the population of these colonies without killing them.  It consist of setting traps to catch the cats, fixing them and releasing them back to the colony. 

If you have cat traps there are many places that spay and neuter very cheaply.  We recommend www.mashvet.net to get them fixed.  

If you don't have cat traps there are a couple groups that can help you.  Below are their links.

Trap and release groups-

www.thefoundationforhomelesscats.org 

Azcats 

http://www.alteredtails.org/TNR-ferals.html  

Please act fast to stop the problem before it is out of hand.