Bluebird houses

The box

NestWatch’s Eastern Bluebird box is 5½ by 5½ in inside and 9 in deep, with walls of untreated wood at least ¾ in thick. The hole is 1½ in round, or an upright oval 1⅜ in wide and 2¼ in high. The oval is narrower than the round hole, so do not read 2¼ in as a round hole’s size.

The hole’s height above the floor is not in our sources: take it from NestWatch’s plan for the box.

Where to put it

Bluebirds hunt insects on open ground, so the box belongs in open grassland or open woodland rather than deep among trees. NestWatch’s bluebird page puts it 4 to 6 ft up on a pole, facing east; its placement table allows 3 to 6 ft. Keep bluebird boxes at least 300 ft apart.

Use a freestanding metal pole with a baffle below the box: a cone about 3 ft across, or a stovepipe about 8 in across and 24 to 36 in long.

After each brood

NestWatch’s bluebird page suggests taking the old nest out once the young have fledged. Its general advice is to leave nesting material while the season lasts and clean when it is over. Either way, open the box only when you are sure it is empty; if you cannot tell, wait.

Checking on the nest

NestWatch’s monitors look in every 3 to 4 days and stay less than a minute. They skip early mornings, bad weather and dusk, stay away early in incubation and in the days before the young leave, and watch from a distance when going closer would disturb the birds. That is a monitoring routine, not a schedule: you never need to open the box to enjoy it.

Feeding bluebirds

Bluebirds seldom take seed. Mealworms, suet bits and fruit in an open dish bring them to a feeder.