I don't know how but sure hope those little kiddies are "fixed"... they can sure multiply fast...
We had neighbors that "left" their little kitty and before we knew it we had a litter of little kitties under their empty house..
I managed to trap them including the momma, brought the little one's to the vet. He was kind enough to help find homes for them..the mama was fixed and a home found for her too..