The migratory lark bunting (Calamospiza melancorys Stejneger) was designated the state bird of Colorado in 1931. The male lark bunting performs a spectacular courtship flight while warbling and trilling a distinctive mating song. A breeding male is jet black with white wings but in winter changes to a gray brown color more like the smaller female bird (the lark bunting is the only sparrow that changes in winter to a drab plumage).

Though the lark bunting is still a common sparrow of the Great Plains, grassland bird species in North America have experienced large population declines in the past forty years. Lark buntings declined by 2.5% per year in Colorado between 1966 and 2003.