fledgling jackdaw been here for 24 hrs

Hey, a fledgling jackdaw has been in my garden for a day now. the rspca said to leave it 2 days, but now i'm noticing that it's becoming weaker - it's not hopping as well, very tired. quite conscientious that i'm in a neighbourhood with 4 different cats. any advice? is it ok to go get some worms and feed it? should I put it in a box? I know that the parents are meant to come by and get it, but it's not looking likely. thanks.