I have a Blue tit who is busy nest building in the nest box which is on the trunk of an apple tree. The camera shows 4 large slugs nestled in the corner and writhing around. She ignores them.
Should I open the lid while she is absent and get rid of them?
Slugs need to leave to feed. I am guessing you have a camera in the box? You should see whether they leave. Worth getting copper to go around nestbox and/or tree, to put slugs off.