The Big Yard: Notes from a Pajama Birdwatcher

Yellow-eyed Junco, the ice-age progenitor of all juncos.

December 11, 2024

At sunrise, ice layers the fountain and sheaths the grass. The air feels leaden, like a solid weight on my skin. Thirty degrees. My camera lens shifts cold aluminum into stiff hands. I pull my blanket tight around my shoulders. But, despite the numb fingers and dripping sinuses, I’m determined about juncos.

Siskins and goldfinches crowd the thistle feeders and the trickling fountain. White-crowned sparrows whistle sweet phrases from the trees. The single white-throated sparrow still comes for water after more than two weeks of daily visits, the rare bird making up for a 12-year absence. And among these, I count a dozen dark-eyed juncos of multiple races, each with striking departures in feather color, body size, and behavior. You’d think they were all different birds.

This time of year, the yard hosts five of the six subspecies of dark-eyed junco: gray-headed, pink-sided, Oregon, red-backed, and slate-colored. The remaining subspecies, the white-winged of the pine-dotted Black Hills of South Dakota, is “accidental” in southeastern Arizona with only two records. And then there are the hybrids. Here, I usually see a cross between the gray-headed and red-backed. Then yesterday, a new, small gray dark-eyed junco with an indistinct hood and brownish back and nape joined the others at the fountain. I’d never seen it before. After I posted it on eBird, the administrators confirmed my suspicion of an Oregon x gray-headed hybrid.

The most common race of winter Dark-eyed Junco in the yard, the gray-headed.

Second to the gray-headed, the pink-sided Dark-eyed Junco.

A male Oregon Dark-eyed Junco with its distinctive hood.

A rare junco for southeast Arizona, the red-backed Dark-eyed Junco. Note the bicolored bill that distinguishes it from the gray-headed.

The slate-colored Dark-eyed Junco shows little or no contrast between the head and back.

I recently learned that a slate-colored Dark-eyed Junco showing some contrast between the head and back is from a separate population in the Canadian Rockies and is now called a “cismontanous” Dark-eyed Junco.

The upper bill of this Dark-eyed Junco isn’t uniformly dark but bicolored, identifying it as a hybrid gray-headed x red-backed Dark-eyed Junco.

The latest hybrid Dark-eyed Junco, a cross between the Oregon subspecies and the gray-headed.

More than any other bird in North America, juncos illustrate the broadest spectrum of obvious variation in a single species.

When I watch juncos, I see a species turning, a slow yet steady gaining of momentum. I see the flywheel of evolution.

From their DNA, we know that all dark-eyed juncos spun off from a single junco from the highlands of Mexico and Central America sometime after our last glacial maximum about 20,000 years ago. The yellow-eyed junco. A common yard bird whose range just sneaks into southeast Arizona from Mexico.

I’m reminded of college biology, adaptive radiation, and the beaks of finches.

When I look at a map showing the summer ranges of dark-eyed juncos—the gray-headed in the mountains of eastern California, Nevada and Utah; the pink-sided in the forested Rocky Mountains of Wyoming and Montana; the Oregon in the woodlands of southern California to British Columbia; the red-backed in northern Arizona and central New Mexico; and the slate-colored in Alaska, Canada, and the east coast—I imagine them all radiating from the home of the yellow-eyed junco. From my yard. Where each one returns in December.

Today, a celebration. I join the winter gathering grounds of juncos.

This morning’s visitation of a rare White-throated Sparrow. I understand that Dark-eyed Juncos occasionally hybridize with these as well.

Thanks for reading! More to come from the Big Yard…