To be clear here, the “territory” here is letting your pet free roam off of your property and expecting everybody else to be cool with that?
It's always so frustrating when you've been doing something for 15 years, speak from experience, and then someone comes along and says "Well, that's bad!" Sure. Meanwhile, my cat comes home happy and healthy each night, unless "everybody else" decides to steal him in the guise of doing him a favor.
Verified microchips during vet appointments would cancel out this exploit.
I have a cat and it stays indoors exclusively.
Using "think of the birds" as a justification for imprisoning your cat for their entire lives is also pretty crummy. It's called wildlife because they exist in the wilderness. Even if cats kill a large number of birds, so what? Those birds don't have a happy, loving home with emotional bonds to an actual human.
If you think this logic is flawed, explain why you're fine with flies dying but not birds. I bet you've swatted a few in your time.
Cats are probably a leading cause of mortality in birds. [2] Domestic cats are not native to North America. The birds here would not have evolved to avoid them (and beyond that, domestic cat numbers are not limited by prey availability because they're pets bred and fed by humans).
You'll find plenty of studies with evidence that domestic cats are probably bad for bird populations. [3][4]
But to be fair, buildings/glass windows kill a lot of birds too. [5]
[1] https://www.nature.com/articles/ncomms2380
[2] https://www.fws.gov/library/collections/threats-birds#:~:tex...
[3] https://www.mdpi.com/1424-2818/13/7/322
[4] https://wildlife.onlinelibrary.wiley.com/doi/10.1002/wsb.737
[5] https://journals.plos.org/plosone/article?id=10.1371/journal...
