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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

Dark-eyed juncos or 'snowbirds' are among the most common birds visiting winter feeders. © Stephen J. Lang
Dark-eyed juncos or "snowbirds" are among the most common birds visiting winter feeders. © Stephen J. Lang

October 2004

The snowbird chorale

Juncos twitter in the fall and winter chorus.

Anita Carpenter

Flaming red maples, fading goldenrods and slow-chirping crickets are all clues that summer is winding down and autumn is sneaking in. The change brings mixed emotions, but one joy is the return of those perky, chunky, six-inch-long slate-gray birds with white bellies – dark-eyed juncos. Traveling in small flocks, these distinctive sparrows appear predictably from the last week of September into the first week of October under cover of darkness. I often hear their soft twitters before I first spot them scratching the ground under shrubbery or hopping from branch to branch in dense foliage.

Along with shorter days and frosty nights, returning juncos foretell the coming of winter. Early nature watchers gave these winter harbingers a name – snowbirds – and their scientific name, Junco hyemalis, reflects their association with winter: hyemal from Latin means winter. Many juncos spend winter with us, but countless others continue south as far as they choose. They delight us from October through March, then push north in April.

Coniferous forests of extreme northern Wisconsin and Canada are the juncos' summer home. Their soft trilling must be a pleasant addition to the symphony of song in the spring forest. Juncos get down to the business of breeding quickly, constructing a well-hidden nest in a grass-lined depression on the ground. The female alone incubates four to five, gray to blue-white eggs speckled with brown. Eggs hatch in 11 to 13 days and the nestlings, tended by both parents, are fed an insect diet. Young leave the nest in 12 to 13 days. After a second brood is hatched and fledged, juncos gather in flocks and head south.

Dark-eyed juncos are easy to identify. They are the only small winter birds with white bellies that are dark gray on the body, head and tail. They have finch-like, conical pink bills and dark eyes. Females and young are lighter gray washed with brown overtones. The friendly, non-feisty juncos are primarily ground feeders, hopping about, scratching the earth, pecking and searching for seeds. If startled, they fly to cover, fanning their tails to reveal white outer tail feathers – a conspicuous field mark to aid in identification.

Juncos are interesting to study. As you peruse a flock, you can't help but notice the subtle variations in plumage. Perhaps you may see a junco with a black head and breast, reddish back, white belly and buff flanks or maybe a light gray junco with white wing bars. They look quite different from the more familiar dark gray forms, but they are all the same species.

Junco nomenclature and taxonomy are confusing. At one time, six color variations (slate-colored, Oregon, white-winged, pink-sided, gray-headed and red-backed) with separate geographical ranges were considered separate species. Subsequently, ornithologists discovered that where the population ranges overlapped, interbreeding occurred. The six "species" were consequently lumped into one species and renamed the dark-eyed junco. To this day, field guides still identify the various populations. "Our" junco is the eastern population or slate-colored junco.

All this taxonomic confusion has not bothered the birds one iota. They go about wandering the countryside, brightening our winters and twittering when most birds are silent. So put out the bird seed, welcome and carefully examine all of our autumn and winter-visiting dark-eyed juncos. If you don't like the notion of a harbinger of winter, recall the lyric in the Anne Murray hit: "The snowbird sings the song he always sings, and speaks to me of flowers that will bloom again in spring."

Anita Carpenter birds year-round from her home in Oshkosh.