Back in my old neighborhood, this gray cat used to give birth in either my neighbors or my yard all the time. I don't even remember how many litters of kittens she gave birth to. I swear it was like once a year, sometimes two. My neighbor wanted to call animal control but his wife told him to just let the cat be since she wasn't bothering anyone. That was true, except that if the cat saw you outside, she would walk towards you, meow, turn around so her behind is towards you and lift up her tail.
One time she was giving birth in my neighbor’s garden shed and one of the kittens only came out half way, so they had to call a vet over. He pulled the kitten out but it was already dead. The mother was fine though.