Laura Erickson's For the Birds

Tuesday, December 6, 2011

Juncos!

Dark-eyed Junco

Transcript of Monday's For the Birds

One of our most abundant, familiar birds is also one of the most taxonomically confusing. A 1995 estimate set the Dark-eyed Junco’s total population at approximately 630 million, and John James Audubon wrote in 1831, “There is not an individual in the Union who does not know the little Snow-bird.” Common as juncos are, Audubon was exaggerating their familiarity a wee bit—when I started birding as an adult, I’d never heard of them, and I had no clue when I saw my first at my in-law’s place in a Chicago suburb on March 21, 1975, that the junco was the bird sung about in Anne Murray’s “Snowbird.”

Dark-eyed Junco

In teasing out its identification in my Golden Guide, I saw that there were 5 species of juncos in the United States—fortunately, the birds I saw were very typical Slate-colored Juncos, the one described by Henry David Thoreau as leaden skies above, snow beneath. I loved how easy they were to identify. If they didn’t sit still long enough to give me a satisfying look, they’ve give away their identity when they spread their tiny wings and flew away, showing off their white outer tail feathers like lovely streamers.

Dark-eyed Junco

Our common slate-colored junco also ranges throughout much of the West. The other birds considered separate species in 1975 were the Oregon Junco found in much of the West, the Gray-headed and White-winged Juncos with more restricted ranges in the West, and the Mexican Junco, found in western Mexico and Southeastern Arizona above 5,000 feet. In 1983, four of the species were lumped into one species, called the Dark-eyed Junco, and the Mexican Junco became the Yellow-eyed Junco. When Russ and I went to Arizona last month, I got to see other varieties of Dark-eyed Juncos, along with some gorgeous Yellow-eyed Juncos in the mountains outside Tucson.

Yellow-eyed Junco

Most of us in the upper Midwest see only the typical slate-colored variety of Dark-eyed Junco. Even so, our juncos vary, including the intensely-dark older adult males, the paler young adult males and adult females, and young birds which may be streaked as well as being pale. But every now and then one of the western forms appears at our feeders, too, making the birding more interesting.

For scientists, juncos are perfect research subjects. They can survive Canadian winters and are easy to maintain in captivity. In laboratories juncos have been subjected to extremely cold temperatures and long day lengths to establish that it’s the increasing photoperiod, not weather, that makes birds physiologically get into breeding readiness, even though weather has a huge impact on breeding behavior. If juncos are easy to study, they’re extremely difficult to classify. Many researchers believe that DNA analysis will lead to more changes. One day I may well be reading some ornithological news at breakfast and discover that I’ve got brand new lifers, thanks to having seen Dark-eyed Junco varieties that will turn out to be different species.

Dark-eyed Junco

Whatever their classification, juncos are easy for just about anyone to watch and photograph, at least anyone who is a little more aware of them than I was before I became a birder. I’ve gotten lovely close-up photos of them in my backyard simply by setting up my photo blind near where I put out birdseed. Right now, juncos are the most abundant birds in my backyard. As winter progresses, some or all of them will wend their way south, but right now I’m taking great pleasure in my little snowbirds.

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