I have a colony of approximately 30 cats living in my yard. They came because there's food, shelter, and security here. Yesterday, a white cat crossed the border of our street to find food, which he has done a few times before. This time, however, one of the older residents decided to be territorial and took a bite out of the white cat's ear.
Now which cats in my yard "deserve" to be here? A few were born in my woodpile, but most were abandoned or came from other yards where the food supply was gone. Some had to avoid my neighbor, who shoots cats with his BB gun.
Obviously, some came after others, and they had to be persistent in order to gain acceptance. Females and kittens rarely succeeded without my help. Some gave up and left, probably dying of malnutrition or some brutality on the streets. Food is expensive, so is their medical care.