ROWDY TREED A FERAL CAT

In my neighborhood the city traps a feral cat that lives in the area and neuter or spays it and notches the ear so they know it’s been fixed.
They let the cat go and it lives in the ’hood and keeps other strays away. They started the program 6 or 7 years ago with a tuxedo kitty that hung out in my yard. I honestly didn’t lend much credence to the scheme but it’s kept the feral cat population down until just this year. I noticed last spring there were more feral around. The tuxedo is getting old and even though he’s around he’s not as robust about keeping others out.
I've notice the same thing with squirrels. If I leave some of the bigger males alive in my backyard they tend to keep all the other smaller ones away. If I take out every squirrel that comes into my yard it'll be quiet for a few weeks but they come back in much bigger numbers.