Looking back at the video and from watching Fyfe yesterday, I suspect that he fledged by accident Sunday morning. Both he and Carson were wingercizing and off they went together. Kind of hard to tell but I suspect Fyfe followed Carson. Carson has been a couple/three days ahead of his male sibs throughout development so he may well have been fledging on schedule and Fyfe decided to follow. Fyfe has been following his brothers a great deal of the the last week. Carson hopped to the ledge first, followed by Cade a day later, then Fyfe made a couple of forays, but he wasn't nearly as strong or confident as Carson or Cade on the ledge or on the box edge. Watching the three boys, I suspect that Fyfe might have been our last hatch on the 26th, which would have made him 38 days old when he fledged, 39 days old when he died. The 39-42 days old is right on the borderline, so technically, Carson is borderline as well and until we see him again we won't know how he has fared either. Some birds have done fine fledging early, older birds fledging later have come to harm, so no real way to tell, its all up to the fledgling I'm afraid.
We'll let you all know if we catch sight of Carson today ...