The best course of action is to summon the Humane Society near you and have them set traps. They will safely and humanely trap the kittens, and will socialize them for adoption. It may be difficult to socialize the mother cat, but if there is a way to do it, the Humane Society knows about it and will do what they can do adopt her to a kindly home also.
However, I must note that feral kittens, once adopted, can be quite dangerous! When you sit down with that kitten in your lap and scratch gently on his ears, that will cause him to vibrate. If he REALLY enjoys your company, he will vibrate more loudly still and that can cause your house to shake off the foundation.
You will also find that the adopted kitten may develop Lapitis: whenever he sees a lap, he curls up in it and becomes terminally cute. Some kittens also have designs on curling up beside you when you go to bed, and will do anything to have you drag a string across the floor for them to chase.
Even worse, you may find that the kitten follows you all over the house, rubs against your leg, and becomes a very affectionate companion. Of course, puppies and kittens can cost you all your loneliness.
When you consider the unconditional love dogs and cats give us, and the precious little that they ask in return, it can become a habit to be very kind to them, give them decent food, a good place to stay, and lots of your time.
Come to think of it, I like that. I have three cats. Some little darling stuffed her and three of her sisters in a cardboard box, and left it beside the road. When I walked near the box, I heard meowing inside, and opened the lid. I took the kittens home and called the vet for instructions on how to bring them back from the brink of starvation. The kittens nearly starved. One didn't survive. I broke down crying over that.
He paid a visit with IV fluids and treated them for free. They have been my constant companions ever since, and have never again wanted for love or seen the inside of another cardboard death-row cell.
Somehow, I have an attitude about it when people mistreat animals.