Wasps and bees seldom usurp boxes from nesting birds. They are mostly found in empty boxes. If these insects are found in a box, it is best to let them be and not take any active measures to exterminate them. Instead, wait to clean them out in the fall when the weather is cooler and their activity has halted. You can prevent wasps and bees from establishing themselves by applying a thin layer of soap (use bar soap) onto the inside surface of the roof. This will create a slippery surface between the insects and the roof of the box. For more information about maintaining nest boxes, visit Nestwatch.
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