how do we rescue a baby Robin from our patio?

We currently have a baby robin who has tried to fly the nest but not ready yet so stranded on the patio and the parents were feeding it this morning but haven't seen them this afternoon - do we try to handle it and put it in the nest? we're not sure where the nest is, somewhere in our Ivy bush

Any help much appreciated. I'm also trying to keep our cat indoors but she's getting very tetchy!

Thanks, Liz