Yep, we had one TNR cat on our block. I fed him. A lady up the street adopted him last year, made him indoor. Now we have ground squirrels running all over the place. And that's only what I see. Who knows at night. Things usually end up in a balance over time. When someone, or something, interrupts, it takes a while to get things back into balance. It's always been interesting to me how that works out.When we moved to the NW into our senior MH park there was a lady who cared for a small group of feral cats. Most residents resented the cats & was always complaining about them. Once I had a chance to talk to the care giver I learned a good lesson. She fed 4 of them, had all their shots, neutered them & fed them on a nightly basis, she paid for all the care & doctoring. I'm not a cat person but now I recognize the benefits they preformed.
They kept all the other strays at bay out of our park, kept the vermin population at a minimum & never bothered us. She had also setup & maintained 4 or 5 litter boxes around. No smell stayed away & were not pests. Some of the do-gooders got on the 'Remove the feral cats' bandwagon & finally forced the lady to give up her cats. A few years later the park management had to pay for the trapping & removal of vermin (mice & rats) along with more feral cats now showing up in the residents yards & garbage cans.