Well I was way off with the timing on the fledge of my 5 young ones. They must have fledged on Friday or Saturday (day 15 following the hatch), when there was a lot of activity with mom and dad bird in and out of the nest box. I watched on Sunday and Monday and never saw either of the birds but yesterday (Tuesday) both looked into the nestbox , then flew away. I checked the box and it empty. It is cleaned up and ready for the next brood. I am assuming that they will return an a week or so to begin the second nest.