Provide ventilation. Drill small holes ƑǞ to 1ǚ_inch diameter) through each side of the birdhouse just below the roof. This will provide better air circulation. Do NOT add perches. Perches allow predatory birds (like jays, magpies, ravens, and crows) better access to the eggs and young in a nest box. In contrast, cavity_nesting birds rarely use perches and prefer cavities without perches.
Predator Protection: Backyard predators that threaten bird houses can include pets, stray cats, raccoons, rats, squirrels, snakes, mice and even stinging insects. Other bird species may also kill or injure baby birds and their parents either for a meal food or to take over the house for their own nesting site. To make a bird house safe from predators. Remove any perches from the house: Birds do not need them to access the house, and perches only provide convenient handholds for predators. At the same time, remove any nearby branches that could also provide a way for predators to access the house.