Those are pieces of wood with channels cut along the length of them. After you put a thin plank on top the earwigs crawl in there for shelter during daylight.
That's the thumbnail for a video on how to make them.
Mine have been moved because of work going on in the backyard, but I'll try to find them today.
I almost lost a couple of young plants to earwigs a few years ago until I cut their population down with the traps.
A piece of cardboard laid flat on the ground works too, but you have to be pretty quick stomping them when you lift it. Those little buggers are fast.