Bluebirds prefer their nests facing – in order of preference – east, north, south and west, though they may choose a house that faces a different direction. Some bluebirds may even begin nest building in the birdhouse and abandon it later if it is not suitable, even to go as far as leaving their eggs. When setting up a bluebird nesting box, several factors require careful consideration for a happy bluebird home.
A Question of Safety
For bluebirds, the question of direction does not always refer to compass bearing, but rather the orientation the house opening faces to afford safety, comfort and convenience after the bluebird pair mates. If placed along a road or highway, the bluebird house should open parallel to, or away from the road so the birds will not be hit entering or leaving their nests. Ideally, the nest box's opening should face toward trees or shrubs within 100 feet so young bluebirds have a place of safety for their first flight.
Situate the nesting box to face an open area that allows access to trees and low vegetation. This makes it easy to catch and feed the hungry brood insects after hatching. After setting up nest boxes, monitor them to help improve nest survival, as well as to identify any issues that may arise to correct them. To help attract bluebirds to nesting boxes, set up a food station that includes mealworms. This also helps the female by having food close by while she incubates the eggs.
Comfort and Protection
Regardless of compass orientation, bluebirds prefer nesting boxes with openings facing away from prevailing winds that might blow rain into the house, as well as away from midday to afternoon sun that overheats the inside. Bluebirds will initially choose a house regardless of the direction it faces. If it is positioned incorrectly and later becomes unsatisfactory for them to live in, they may leave the house and abandon their eggs.
Type of Nesting Box
Bluebirds prefer a box with a small round opening closer to the top, with the body of the box available for a protected nest. Leave about 6 inches of box beneath the oval opening, with the front of the box about 9 inches tall and the back about 13 inches tall, creating a slanted roof or flat roof as desired. The opening size depends on the type of bluebird in your area, for example, eastern bluebirds require about a 1 1/2-inch diameter opening, while mountain and western bluebirds need an opening of about 1 9/16 inches in diameter. The entire nesting box can be constructed from a one-by-six inch board roughly 5-feet long. Set the nesting box height based on the bluebird breed from 3 to 6 feet above the ground.