they might have chased him out cause he doesn't smell or seem right. he has been to places unknown, and touched by hands. mommas will push a baby right out of the nest when that happens.
When I was a little girl we had a baby (and I mean BABY) red robin land on our porch from an overhanging tree branch. We put it in a shoe box and lined it with cotton balls and newpaper. We were so afraid the mom would not come and clean it or feed it. We bought some baby bird food and a syringe to feed it. but no matter what it just wouldn't take it. we even tried forceful feeding. not happeneing. it was getting weak, and my mom taught me about death to prepare me. upong getting up on time i accidentally tapped the side of the box, jolting it. the baby bird just went nuts and held its wide open mouth up high. it needed that mocking of the momma landing on the nest to know it was feeding time. it ate like a champ, and we took care of it till it flew off on its own. i will remember that forever, and it was prolly one of the best ways for a kid to learn about life. it also made me fall in love with how nature works.