The role of the nesting cavity remains important throughout nestling development, as young remain in the nest dependent upon parent bluebirds until fledging roughly 15 to 18 days after hatching. Optimal nesting habitat contains up to seven suitable cavities per acre and an adequate number of perches from which to forage in close proximity to foraging habitat. In areas that lack snags or natural cavities, nest boxes can be used to augment the availability of natural cavities. In areas where bluebirds winter, habitat requirements differ little from nesting or summer cover types. Woodland edges, fence rows, open fields, mowed yards, cemeteries, and farmlands provide adequate winter cover needs when mixed with snags, open grassy areas, and wild fruitbearing trees and shrubs.
Nest boxes can provide roosting cover for bluebirds in winter months as well.
Due to the variability in climates between the cooler, northern reaches and warmer, southern reaches of the bluebird's range, available food sources may differ but habitat requirements remain constant. The year-round availability of insects determines where bluebirds winter.