Monitor
Monitor Monitor!

Open the nestboxes at least once a week until the nestlings are 12 days old. Check after a heavy rain for wet nests, which can be replaced with dry grass. Keep blowfly larvae out of box. Remove a dead nestling immediately. Remove old nests after young have fledged, and before the second nesting begins.

After the nesting season, if house sparrows are in the area, leave the door of wooden boxes open, and tape the entrance hole of PVC boxes. The next spring, no sooner than
April 1 in Minnesota, close wood doors and open PVC holes.