Raccoons and some other predators also caused damage this year. Marijke Jalink-Wijbrans noted “…a raccoon discovered our trail and dined on about 47-65 young Tree Swallows.”
How can we guard against raccoons? We have been recommending driving a screw into the base of the box in order to prevent a raccoon’s pushing up the base. Even this may not be enough. We may need two screws in those areas where raccoons are prevalent. Many years ago they were only south of the border, but they are moving north! Climate change?