It’s normal to catch only male HOSP right now with your Van Ert trap. You start catching females when the males lure them in and they are bonded with the house. Do you use a bag over your nestbox to remove the trapped bird? That’s the easiest. You don’t need one trap per box. Usually you just move the trap around. And remember, never leave the trap while you go to the store. Has to be monitored well.
Tammy