Give them shelter. Mount a nest box that meets the specifications of the North American Bluebird Society. A good bluebird box should be well-ventilated, be watertight, have drainage holes and be easy to monitor and easy to clean. Place the nest box in a semiopen grassland area about 4 to 6 feet above the ground to attract bluebirds.
Feed them. Bluebirds feed mainly on insects in the summer and wild berries in the winter. Providing mealworms in a plastic feeder will greatly increase your chances of attracting bluebirds. Mealworms can be bought at local wild bird supply stores. You can also plant fruit and berry trees.
Offer water. Water sources, such as birdbaths, are a great draw to bluebirds. Birdbaths should be no more than 3 inches deep with sloping sides and have a rough surface to provide good footing. Change the water every 2 to 3 days to keep it fresh.
Provide nesting materials. Bluebirds like soft grasses and pine needles as nesting material. Gather and leave these materials close to the nest box to attract them to your yard and encourage them to nest.
Monitor the nest box. Check the box at least once a week during spring and early summer. Contrary to popular belief, opening the box will not hurt the birds. Record the number of eggs, the date the eggs hatched and the number of young. This information is useful for determining bluebird population trends.