I've posted a video of our yearly falcon banding here in St. Louis. We monitor populations of peregrine falcons at various locations around the area. Banding chicks allows us to keep track of population health and movement. Plus, they are cute. Falcon chicks are my personal favorite.
The banding process in no way injures the chicks and is a common conservation practice around the US. They do, however, protest loudly at such rude interference! I hope you enjoy the video.