What about bees or wasps that begin nesting inside my plastic barn owl box?

Occasionally, wasps may nest in the space between the inner liner and the outer box. They tend not to harm the birds, and also are usually fairly non-aggressive. Since your interactions in the box should be kept to a minimum during breeding season, the best thing to do is just let them be until the birds have fledged. Honeybees (especially Africanized bees) present quite a danger to humans and the birds, however, we do not have a single instance of honey bees taking over one of our plastic nest boxes—perhaps because the plastic surface does not allow them to begin building their nest. Nonetheless, any sign of honeybees near or in a nest should result in exercising great caution and the proper county authorities should be called in.