Since nobody else has mentioned it: rats in NYC are frequently poisoned and are dangerous for predators to eat. The city has had a number of famous hawks and owls die over the years due to poisoned rats, most recently Pale Male[1].

I have a feral cat that lives under my stoop, and I like it. But I’m also not under a bucolic daydream about a closed ecosystem between this city’s cats and rats.

[1]: https://www.nytimes.com/2023/05/17/nyregion/pale-male-hawk.h...