I have to wonder that the kids might be able to fledge better from a higher up location - nestbox - than rather the flat roof where they have to jump up to be at a vantage point.
Is there a difference in advantage for the kids?
I've seen chicks fledge from the nest box all survived and didn't bomb out, they simply soared across to the tower or to the annex and next day were on the Scotia Towers. Didn't TPC say that Brandon was a safe place for fledging chicks and that there were less problems here than in Winnipeg and that there had been few problems over the last 20 and counting years. And in the normal course of events isn't fledging from high places the norm for Peregrine falcons and do humans really have the right to play God?
Play God? A bit dramatic since the difference between the roof nestbox and the wall nestbox is about 20 feet. On natural cliffs, chicks often move from one ledge to another (if available) and often more than 20 feet away from the original nest scrape. Once they are mobile, the chicks will wander as far as their environment, their confidence and their strength will allow. The Radisson chicks use the ledge beside the nestbox because that is what they want to do - that ledge is also about 20 feet long. So the argument could be made that when we have put the chicks in the roof nestbox after banding we are actually just mimicking, or rather facilitating, natural chick behaviour. I realize that it is easier to watch the birds when they are in/on the wall nestbox than when they are on the roof but when we consider what to do, it will be to decide what, if anything, might improve the chicks' chances for survival. Just as I am sure you would rescue a chick if after fledging it landed in the middle of the road. Neither actions are a guarantee the chick will survive its first year, but they could well improve the chick's chances.