Lazuli Bunting

by Denny Olson

T. S. Eliot once used the phrase “ Water out of sunlight” when referring to the refractive blue color in a pool. I have no way of knowing this, but I suspect he never watched a little azure jewel drop out of the sky and land on a shrub in the American West, or he may have adjusted his metaphor to claim that Lazuli Buntings are feathered beings made of sunlight. And he would have been more scientifically accurate had he done so. In birds, and also in glacial lakes, the color blue is indeed made out of sunlight, prismatically refracted (bent) light from the barbules of the barbs of the vane in a feather. In the Lazuli Bunting male, the color is almost neon – named after the lapis lazuli precious stone. The stone is pretty, but the bird is stunning, and the stone should probably have been named after the bird, instead of the other way around.

Lazuli Buntings are small finch-like birds more closely related to Cardinals, Dickcissels and Blue Grosbeaks than to the finches. They can be easily distinguished from other “blue” birds by looking for white wing-bars. The Passerina genus (of which the Lazuli is amoena, meaning “lovely”) contains some beauties – the Painted, Varied, Indigo Buntings and the Blue Grosbeak. All of them have blue feathers, which are actually clear and prismatic, making the color (ahem) a pigment of your imagination …

In our part of the Lazuli range, scrubby and shrubby south-facing slopes seem to be preferred habitat. They nest near the ground in brush about head-high, and if there is an exposed perch a bit higher within their territory, the resident male will often sing his threatening songs from there.

The songs themselves have the same buzzy, scratchy, high-pitched quality, but the cadences, order of phrases, and length of the songs are different … for every single bird, everywhere! They are a barcode of individuality, and every Lazuli male can tell where every other male is within earshot.

When juvenile males head south in late July and August, they don’t have their own song. They probably practice short squawks and tweets on their Southwestern Mexico wintering areas, but their rite of passage to adulthood does not come until they arrive back in suitable habitat the next spring. They find a spot to reside, and then they “borrow” short phrases from all the surrounding adult males, and construct their own version of “Lazuli-speak” – and use it to carve out their own territories. The net effect is Lazuli “neighborhoods”, where the songs all have some familiarity to each other, but are slightly different.

The males also have black upper bills, but lighter blue lower mandibles, which reflect invisible-to-humans ultraviolet light and may have something to do with mating rituals. The Sadie Hawkins-inspired females solicit mating with low-body, tail-up postures.

Because Lazuli Buntings leave fairly early on their autumn migration routes, they “take a month-long migration break” to molt their feathers in two very specific places – before continuing south. For September, one can find them either on the very southern tip of the Baja Peninsula, or along the border between Southeastern Arizona and Northern Sonora, Mexico.

In a variable band from North Dakota extending to New Mexico, the ranges of Lazuli and Indigo Buntings overlap, and it is not uncommon to see “Indizuli” Buntings (I made that up …) with white bellies and white wing-bars. In other words, interbreeding is fairly common. Probably because of human beings planting trees and shrubs in what was once unbroken prairie, the interbreeding zone has moved west into Eastern Montana and has also narrowed – which suggests that the Indigo Buntings are winning the breeding war.

Lazuli Buntings have variable conservation status. In some areas they seem to be doing OK, and in others they have literally disappeared. In areas of Eastern Montana, Brown-headed Cowbird brood parasitism is nearly 100 percent, and in the 1980’s and 90’s, some populations in Montana were temporarily extinct. Lazuli chicks cannot compete well with the invader cowbird in nests.

As usual, we need to know more, especially on the effects of Cowbird parasitism, habitat change and climate. For “eye-candy” like the Lazuli Bunting, losing them would be a large hole in the beauty of our world, and, as is usually the case, would have ecological repercussions we have yet to discover.