Why Are Buntings All So Good?

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One spring morning, scanning the treetops in Central Park, I spotted a smear of ultramarine against the paler blue of the sky. I raised my binoculars, tweaked the focus, and there it was: an Indigo Bunting. I stood transfixed.

While it was a treat to spot this bird in Manhattan, seeing an Indigo Bunting isn't exactly difficult; they’re among the most common songbirds in the East. It wasn't a lifer for any of the folks I was birding with. And yet, on a morning when we saw grosbeaks, orioles, and an embarrassment of spellbinding warblers, the consensus held that a highlight of the morning—maybe the highlight—was that brilliant bunting.

On the walk home I thought with envy of the Southeastern birders who regularly encounter absurdly beautiful Painted Buntings. Then I envisioned the more subdued but no less lovely palette of the Lazuli Bunting that graces the West. And jeez, could you imagine hiking some desert Southwest canyon and stumbling across a Varied Bunting in its hues of mixed-berry jam?

What, I wondered, is going on with buntings? Why are they all so good?

Like any self-respecting bird journalist, I felt duty-bound to look into it. So I called up Kenn Kaufman, renowned avian expert and Audubon field editor. Before we could delve into why these birds are so extraordinary, though, we first had to address another question: What is a bunting, anyway?

As with many questions of taxonomy, the answer is slipperier than you might think. The birds first referred to as buntings, Kaufman explains, were European species from the genus Emberiza. Some of these species, such as Little Bunting and Rustic Bunting, occasionally stray into Alaska, but none are resident to North America. "And they don't look nearly as cool as our buntings," he says. Take that, Emberizidae.

When early naturalists began classifying North American birds, Kaufman tells me, they slapped the sparrow, finch, or bunting label willy-nilly on just about any species with a thickish bill that looked good for cracking seeds, since that's what such birds were called back in the Old World. In the early 19th century, ornithologist Alexander Wilson used Cow Bunting for what we call Brown-headed Cowbird, Rice Bunting for Bobolink, and Bay-winged Bunting for Vesper Sparrow. John James Audubon's Ornithological Biography, published in the 1830s, labeled our Henslow's Sparrow as Henslow's Bunting. Confusingly, Audubon also referred to Painted Bunting as Painted Finch. And Smith's Longspur? Painted Bunting, of course.

In 1886, when the American Ornithologists’ Union published its first North American bird checklist, species names became more standardized and things began to make a bit more sense. By that point, many birds previously called buntings had been renamed as sparrows or finches. And in the checklist, most birds that we call buntings today shed their older labels and took on their familiar names.

Among those birds, the real stars of the bunting bash are the six species in the genus Passerina, part of the cardinal family: Indigo, Lazuli, Painted, and Varied, plus two dazzling species endemic to Mexico: Rose-bellied and Orange-breasted. "They are, all of them, among the most beautiful birds in the world," Kaufman says.

The American Ornithologists’ Union's first official North American checklist used the delightful names Snowflake and McKay's Snowflake for what we now call Snow Bunting and McKay's Bunting, respectively. White birds of the far North, both belong to the genus Plectrophenax, are unrelated to the rainbow-toned buntings of the South, and are part of their own family, which includes longspurs. Meanwhile, the Lark Bunting of the western Plains, is something else altogether: "It's just an American sparrow that's a little fancier," Kaufman says.

(Unfortunately, some unsavory characters share Kaufman's assessment: In April, state and federal wildlife agents in Florida seized more than 500 birds and charged 10 defendants with alleged involvement in wildlife trafficking. The birds included Indigo, Lazuli, and Painted Buntings, along with other colorful and desirable species.)

I was glad to have expert confirmation; my buntings-are-good thesis would survive fact-checking. But I still wasn't clear on why. For that, I contacted Richard Prum, an evolutionary biologist and ornithologist at Yale University.

His answer: "Buntings are so cool because they’re cool to themselves."

That's classic Prum. He is well known for championing a view of sexual selection rooted in aesthetics: Animals choose mates they find beautiful not because beauty indicates a fitness to pass on good genes or provide some other measurable benefit, but because it is pleasing in itself. Or, as Prum sometimes simplifies it: Beauty happens.

This notion of subjective, arbitrary choices as engines of evolution is not without its detractors. But Prum argues that it is truer to Charles Darwin's theory than is the competing view—that bold colors, ostentatious tail feathers, and elaborate mating displays are signs of some underlying, objective advantage. "You need to incorporate a concept of beauty as a property of the world in order to scientifically explain it. That's a profound way of looking at the world," he says. "Buntings are an awesome on-ramp for that whole adventure."

It's a testament to their extravagant beauty that, for a 2008 paper that laid out a new system for measuring bird color, Prum chose buntings as his focus. Most birds’ eyes contain four cones, he explains, one more than we humans have. That adds a whole other dimension to their vision and enables them to see colors we cannot detect; a male Painted Bunting appears magnificent enough through human eyes—now imagine how good he must look to the potential mate who can appreciate the ultraviolet green on his back. "To understand how cool buntings are to themselves, we had to invent a whole new science of avian color," Prum says.

My reporting was turning up evidence that buntings are even better than I’d realized. Maybe I would need a few more college degrees to truly understand why, but I could see the big picture. Beauty happens—good enough for me.

I just had one last question for Prum: If generation after generation of female buntings keeps choosing decadently colored males, will there eventually emerge some uber-bunting whose vibrant beauty we can't even imagine?

He responded with a question of his own, one that put me right back in the funky haze of the freshman dorms: "Don't we already have buntings that we couldn't imagine?"

Whoa.

To illustrate his point, Prum shares a brief story. On a recent visit to Arizona, he and another birder came across a male Varied Bunting. Its deep colors were beautifully bathed in morning sunlight. "And this guy is just, like, beyond our imagining," he says. "Really beyond our imagining. When you look at the richness that we’re all engaged in because we love birds—I mean, that's the world we’re already living in."