One of my most favorite things to do is be present when the Peregrine falcon chicks are banded in the Twin Cities' area. My job at The Raptor Center allows me to work with all of the Midwest state coordinators who band peregrine chicks for 13 states. It is a lot of fun to be a part of this ongoing research.
There were four chicks at the Colonnade building - three boys and one girl. They are banded at about 19-23 days old. Their legs are the size they will be as adults, so the proper band size will be put on. They are also not ready to fly yet, so will not be in danger of flying off a nestbox ledge. The first photo is the adult male preening outside the nest box - check out the view he has!