The Best Wood Bird Houses

Materials

• Wooden birdhouses should be made using untreated wood. Treated wood can give off fumes that are toxic for birds. Cedar pine and yellow poplar are best according to Karen Nelms with the University of Tennessee Extension Service. The wood should be at least 3/4-inch thick to provide insulation for birds during cold snaps. While the exterior can be smooth, the interior surface of the house needs to be rough, grooved or cleated to allow young birds to cling to it. Use galvanized or aluminum nails, and glue the joints to keep the birdhouse together longer.

Entrance Hole

• The entrance hole should be sized appropriately for the bird species you want to attract and to keep out species you don't. Adding a predator guard around the hole provides extra protection from birds and animals that might try to get at the nest. A predator guard is just a small piece of wood about 1-inch thick that fits around the entrance hole. This wood prevents raccoons and cats from reaching inside the nest and keeps rodents from chewing around the hole to make it larger. One feature that should not be added to the house is a perch. Perches allow easy access for predators.

Additional Features

• Two additional features that a wooden birdhouse needs are a hinged side or roof and a recessed floor. The hinged side or roof allows for access in the early spring when it is time to clean out the birdhouse in preparation for this year's coming birds. Add a sturdy closing mechanism to prevent raccoons from opening the birdhouse. Don't use hook and eye latches because raccoons can easily open them. The floor of the house should be recessed at least 1/4-inch from the bottom of the sides to prevent it from rotting.

Roofs

• The roof of the birdhouse should be designed to protect the birds from the weather. A slanted roof won't collect water like a flat roof. Adding a strip of metal or roofing paper can add additional waterproof protection. Roofs should also overhang by 1 or 2 inches to protect the entrance hole from rain and shade it from the sun. A 2-inch overhang will also protect inhabitants from cats, according to a University of Maine Cooperative Extension bulletin on birdhouse basics.

Ventilation and Drainage Holes

• A good wood birdhouse doesn't limit itself to only one hole. Beyond the entrance hole, it also has drainage and ventilation holes. Drill four 1/4-inch holes in the bottom of the birdhouse for drainage. Drill another four 5/8-inch holes at the top for ventilation, two on each side of the birdhouse.

Exterior

• Paint or stain the exterior of a wood birdhouse to protect it from weathering. Only the outside of the house should be painted, however. The inside or entrance hole should remain natural. Use earth tones like brown and green to help them blend in; Esther Lutz, East Central Illinois Master Naturalist says to avoid brightly colored houses. The only exception is purple martin birdhouses, which should be painted white to reflect the sun and keep the house cooler.