Sounds like a raccoon. Are you sure they really fledged? You do have a raccoon baffle, right?
Bluebars

Yes, they fledged. Parents and siblings from first brood are feeding them in the treetops. The wing was about 25 feet from the nestbox. I have a baffle on the box. There is a later post on this subject by me. one of the babies was found dead in the box. It appeared to be about 10 days old. The wing did not belong to the dead bird in the box.

Linda C

Linda can you get us a picture or have some one take a picture of the bluebird box, the surroundings, and the baffle. Pictures are worth a thousand words.

Hope we can figure it out, I don't know if I will be much help, but I know some of the more dedicated ones on this forum will be of more help.
sincerely,
Keith

Several birds have fledged successfully from this box. The wing was a good 25 feet away. Two birds did fledge successfully and are in the treetops now. The nest was undisturbed so I do not think anything got the bird from the nest. I think it landed on the ground and was scooped up by a predator. I really do not think a picture of the nestbox will tell us anything.

Linda C

I just read my post and it seems a little curt. I'm sorry; I certainly did not mean it that way. The little dead bird in the nest was all dried out and hard as a rock. I think it had been dead for more than a week but was too large for the parents to take out. The wing that I found ~25 feet away from the box still had moist flesh on it. That's why I think it was a hawk. Although a raccoon could have taken it. There was no other sign of the bird.

Linda C