Ideal nesting and foraging habitat for Eastern Bluebirds is described as low vegetation in relatively open landscapes with a scattering of trees and shrubs with little or no understory. That sure sounds like a suburban lawn! This habitat works well because of how bluebirds search for food. They perch on a tree or shrub to visually scan the ground for insects. Once food is spotted they drop to the ground and capture their prey. A return to the lookout spot begins the process again, unless the captured food is headed for the gaping mouth of a nearby nestling. During summer breeding season bluebirds’ diet is almost exclusively ground insects including grasshoppers, crickets, butterfly and moth larvae. In fall and winter months a portion of the bluebird diet includes the fruits of native plants.
Eastern Bluebirds are secondary cavity nesters. Primary cavity nesters build a new hole each year. This group includes most woodpeckers. Secondary cavity nesters have learned to utilize old woodpecker cavities for their nests. Besides bluebirds, chickadee, titmice, nuthatches, Tree Swallows, and House Wrens compete for these locations. This is why nest boxes in a suburban yard setting work so well. The habitat is right and the presence of nesting cavities make it even better. Building the right nest box and placing it in an ideal location will increase your success at attracting bluebirds over the other species. An excellent source of specific information is: A Guide to Bird Homes by Scott Shalaway.
Rarely, Eastern Bluebirds visit suet feeders or take homemade peanut butter/corn meal mixtures. Many folks attract them by offering live mealworms. A well placed birdbath will often lure them into view once they are nesting and foraging on your property. Whenever they are nearby the soft, low-pitched warbles of the singing male can be enjoyed by all.
Gowaty, Patricia Adair and Jonathan H. Plissner. 1998. Eastern Bluebird (Sialia sialis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology.