You are in a bit of a dilly of a pickle. How to remain diplomatic, as it is your neighbour after all, yet they see fit to lecture you. The way I see it, you have options.

1. Punch in face and knee in nuts, tell them to mind own fucking business. Then piss on lawn.
2. Take down bird feeder and agree to attend "rally for climate change" with neighbour while wearing man-dress.
3. Ignore.
4. Tell them you appreciate their concern, but you too are an animal lover and see things differently.
5. Tell them you are gonna get right on it, but never get right on it.
6. Sell house at massive profit, move to countryside, buy thousand birdfeeders with profits and maybe a few dozen cats. Wife leaves you and you wear same clothes everyday, but you have your precious birdfeeders and no one can stop you now! Write book on how you are able to talk to birds. Buy even more birdfeeders with profits from book.