Just found another earwig on one of my small WS trees. I am starting to believe this is what I am dealing with. I guess I need to let the chickens run free, but we're afraid they'll destroy the garden beds.
I have placed bowls with olive oil and cooked salty fish scraps as bait, and the earwigs have swarmed in and drowned. I've probably killed about 2 dozen that way. When the population is booming, as it has been at times in recent years, it's possible to kill 20 per trap per night. Oil plus nutritional yeast, soy sauce or fish seems to be the best bait combo.