This nesting box features an entrance hole and other dimensions that are correct for the Eastern Bluebird. Wooden predator guard is standard on each bluebird house - it keeps starlings, squirrels and undesirables out, while the small floor discourages sparrow nests. The design includes appropriate ventilation, drainage and opens for easy clean-out. Sustainably grown 1" thick Eastern White Pine provides superior insulation. Hand crafted with pride in Maine. Measures 12 1/2"h x 6 1/4"w x 8 1/2"d with a 1 1/2" entrance.