All bluebirds are cavity-nesting species, and all will use bird houses to some degree. Because there are more natural cavities available in the west, mountain and western bluebirds are less likely to use bird houses, but eastern bluebirds often depend on houses for adequate nesting sites. The right bird house dimensions are critical, and the best bluebird house will have an interior floor of 5x5 inches, interior height of 8-12 inches and an entrance hole size of 1.5 inches in diameter positioned 6-10 inches above the floor.

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