Comment by aldanor
2 hours ago
And how can we tell for sure if it's good or bad? Does killing these birds and mammals help maintain the ecosystem balance (due to these birds and mammals not killing billions other animals down the food chain, or not spreading infections and viruses), or the other way around?
A prerequisite for there to even be a chance of cats being involved in ecosystem balance would be for the cats to exist purely as part of the ecosystem, as in being exposed to negative feedback effects to it (e.g. starvation due to overhunting). As it stands, they are being fed by humans and mostly exist outside the ecosystem, and every kill by them only drains resources from the ecosystem.
Not saying you are wrong, but we also feed birds and rodents, intentionally and by the by products of our society existing.
On the other hand, humans have done a pretty good job of removing most of the other predators in the environment. Domestic cats must be replacing some of the natural predation that is no longer occurring.