I'm sure it just depends on what city you live in and how much tax money they have to spend. I know around here animal control does just that - control animals. They do not have the resources to rescue. Unless the animal is a danger or a threat to public health or safety they usually suggest you call a vet or one of the wildlife rescue organizations such as Phoenix. Even then, those arganizations sometimes require you to deliver the bird/animal to them. I don't have any experience with private shelters and injured wildlife, so I don't know what would happen if one of them had been called.