BTW, we put the Robin's box out atop a window air conditioner when he was big enough. He hung out there for a few days and then left. The following Spring I was standing on the back porch, there was a Robin on the alley fence. Low and behold the bird flew to and sat on the window AC unit for a while. He didn't, however, elect to sit on my shoulder or on my head as he once did.
I felt pretty pleased that we had rescued the little guy.