These slots measure one half inch wide and five and a half inches long. That is a full five and a half square inches of ventilation. With other nest box designs, providing even half that much ventilation increases the risk that rain water will run under the roof and inside the nest box. There is no risk that rain water will dampen the nest inside the Chalet. Birds inside nest boxes mounted on trees, wooden fence posts or other wooden structures are extremely vulnerable to predation by fire ants, cats, raccoons, opossums, snakes and other animals.
Some birders believe baffle guards are necessary for increased predator protection.
If the top of the baffle is only 5 feet off the ground, many snakes, cats, and raccoons can reach or jump up to the top of the baffle without touching the pole, then climb up onto the nest box or raid the nest while sitting on top of the baffle. However, the one inch EMT pole is an excellent pole on which to install a baffle guard if desired.