Rikkitic:
Many city cats spend their entire lives inside apartments and never smell the outdoors. I have known some. They seem perfectly happy. I think it is essential that only very young kittens who have never been outdoors are made to live this way. Any older cat will definitely miss its freedom. I once looked after an indoor cat that suffered from major agoraphobia. That cat would have a complete panic attack if it was placed outside or anywhere without four walls and a roof.
My current cats live on a farm. Some go in and out, others never come in. Cats do target anything that moves and mine catch the occasional bird, but what they mainly bring inside are rats and mice. I know cats attack native wildlife, but I wonder if any kind of study has ever been done on the balance between the bad they do and the good that comes from the rodents they remove. It isn't all one-sided.
This could be relevant...
https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=12003469
I have three cats, that spend nearly all their time outside, only come in to be fed, or when it's cold/wet.
Their mother and father were feral cats, and I have raised them from when they were kittens. I got them neutered/spayed when they were old enough to start breeding. Brooklyn vets did them for half price because they were feral cats and they follow/agree with the TNR policy in dealing with feral cats. (Trap/Neuter/Release)
Like yours they most often catch rats and mice, and rarely catch birds. They have 'cleaned up' most of the large rat and mice populations that lived in and around my and my neighbours address.