My nutty neighbor does the same -- puts food out for his "one or two" cats, which attracts every feral cat for blocks. Several other neighbors and I complained to no avail, so we started trapping and releasing them elsewhere. This worked for a bit, but now several more have appeared. No big deal except that they crap all over the yard and walk all over our cars. I don't want to kill the damned things, but geez, there aren't many more options I can think of. Catching and releasing is a major PITA, and animal control wants no part of our complaints.

Good luck!

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1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)