This widespread songbird breeds in brushy habitats from sea level to more than 3,000 meters throughout the western United States and southwestern Canada. Appropriately named after the blue gemstone lapis lazuli, this species (especially the male) has spectacular plumage. Its habit of frequenting bird feeders makes it conspicuous and well known.
The Lazuli Bunting is a persistent and conspicuous singer throughout the breeding season, as was rhapsodized by I. G. Wheelock in 1912: “Long after the other birds, worn out by family cares, have ceased their music, this blythe little ‘blue boy' carols his jolly roundelay from the top of a tall tree” (Erickson 1968). Each male two years of age and older sings only one song, composed of a series of different syllables. This crystallized song tends to be an “acoustic barcode” that is different from that of other individuals. Yearling males generally arrive on breeding grounds without a song of their own. Shortly after arriving, a young male can copy the songs of other males; it soon develops its own song which can be a novel rearrangement of syllables, combinations of song fragments of several males, or a copy of the song of one particular older male. Song copying by young males can produce song neighborhoods, in which songs of neighboring males are similar.
Individuals begin appearing on breeding territories as early as March or April in the southern parts of the breeding range and as late as mid-June farther north. Males tend to arrive slightly earlier than females, and older birds earlier than yearlings. Most pairs are socially monogamous, but extra-pair copulations are common. Although only females incubate, males provide varying amounts of parental care. At some nests, males provide most of the food to chicks, and occasionally brood young.
Lazuli Buntings have a unique pattern of molt and migration. Individuals begin their Prebasic molt during late summer on the breeding grounds, then interrupt this molt and migrate to one of two known molting “hotspots”—southern Arizona and New Mexico and n. Sonora, or the southern tip of Baja California—where they finish molting before continuing their migration to wintering grounds in western Mexico.
Although many Lazuli Bunting populations seem to be stable, others are declining severely or have been extirpated. Nest predation or parasitism by Brown-headed Cowbirds (Molothrus ater) may have spurred these declines; parasitized nests rarely fledge any of their own young.