I agree with several others in this thread: TNR (Trap, Neuter, Release) is the best option. In my city we have a great group dedicated to feral cats, low cost spay/neuter and eartip, etc. Reach out to your local Humane Society if you don't find a feral cat group with a simple Google search. I had 3 cats trapped, neutered, and relocated to a colony with a dedicated caretaker, shelters, etc.- near one of our properties, for free. All I had to do was call and setup a time for them to come to the property and trap the kitties. This is the most humane, and effective way, to control the feral cat population. I also agree that even though management isn't causing this problem, it is up to them to be the solution.