The vibrant hues of the indigo bunting may be seen throughout most of North America during the spring and summer. Indigo buntings are fond of brushy fields and woodland edges, which are abundant in western Pennsylvania.
The brilliant blues that adorn this bird are caused by a phenomenon known as structural color. The birdís feathers are actually black until they encounter light. The internal structure of the feathers diffracts light, creating the dazzling range of blues that the male displays during the breeding season. Structural color is a trait shared by all birds with blue feathers, including the blue jay and the eastern bluebird. In fall, adult buntings lose most of their indigo, fading to mostly brown like the females and young birds.
Indigo buntings are very loyal to their nesting sites, returning to the same area year after year. The banding stationís records indicate that several of their recaptured indigo buntings have lived to be up to 13 years old.