When I went to check on him today ~ I was actually going to take the branch inside as there's another storm forecast for the weekend ~ he wasn't there. But he was on the ground just below the branch. He must have fallen off somehow. So I gently picked him up ( it's very hard) and took him inside and tied him to a piece of silver thread. As long as he didn't get damaged when he fell I'm hoping he'll hatch.
You can see his wings inside, developing. Amazing