We used the plans from NestWatch to emulate a "tree snag" nestbox using a PVC tube. A pair of chickadees found it quite cozy and built a nest inside. Monitoring the snag box for NestWatch, we noted on May 23 their clutch of 8 eggs.
This spring a pair of bluebirds (Sialia sialis) settled into the nestbox, and Bill’s camera system allowed me to get some amazing footage without disturbing the nest. Here the female is laying her first of 5 eggs.