A young male bluebird enjoying my birdbath

A detailed article from NABS (North 

A detailed article from NABS (North American Bluebird Society) on recommended native plantings   which produce berries favored by bluebirds,  and other birds especially some that will retain fruit through the fall and winter when insects are scarce. 

Bluebirds rarely eat birdseed (although they will occasionally take shelled sunflower chips). 68% of their diet is made up of insects such as grasshoppers, crickets, beetles, spiders, and caterpillars. They enjoy mealworms. They may eat suet, especially during winter months. They also like the fruit of plants such as flowering dogwood, eastern red cedar, holly, elderberry,  virginia creeper and pokeweed. Staghorn sumac, although not a preferred food, is an essential winter survival food along with winterberry.