On Long Island NY, they have a Trap-Neuter-Release (TNR)
program for ferals.
This aims to help control the feral population, while being able to
feed
the ferals at the same time.

http://www.nsalamerica.org/pet_talk/feral-cat-spayneuter-program.html

Feral lifespan is only about 3 years, and half the kittens don't
survive.
It's estimated there are 60 million ferals compared to the 70 million
domestic
cats in the US.

My landlord who has a large property constantly had people drop of
ferals,
and even abandon domesticated cats on his property.
He would catch them all and take them to be fixed.
At one time he had about 14-15 cats...he's down to about 4-5 now.