When dealing with kittens, especially neonatal kittens, remember that they are starting their lives, so they can go either way: feral or socialized. "If with mom and they are outside, they can be part of a TNR program. If not with mom, bring them in, and they can be adopted."
Taking in the young kittens
If the kittens were left in a box, take them. If there is no box and you need to step in because the mother doesn't return, find a box, gather up the kittens, and place them inside the box.
The one thing you should not do is nothing. If left to fend for themselves, the kittens will die.
First determine approximate age. One way to tell if kittens are under three weeks old is by eye color. According to Brown, all babies are born with blue eyes. If the eyes are another color, the cats are older than three weeks. "Older kittens are much more mobile, and have all their teeth and claws," he said.