Nature Notes: Dark-eyed Junco
Someone asked me once if I feared running out of topics for these monthly columns. Hah! There is no chance of that! There is such diversity in the natural world, and so many potential story ideas piled up on the desk that my ashes will be pushing up lupines before the backlog is cleared. The story idea on top of the stack was supposed to yield a nice article on wetlands but my brain was hijacked by a little birdie with a pink bill. I hope you enjoy learning more about the Dark-eyed Junco while I delight in watching them pirouette around the tray feeder.
The great Swedish naturalist Carl Linnaeus in 1753 referred to this bird as a “black finch with a white belly.” In the 1800s, John James Audubon fondly labeled the bird as “snow bird,” a nickname that is still in use today. My mother, who late in life was limited by severe arthritis, spent many hours in her easy chair watching birds at the feeders and she simply called the dancing juncos her “favorites.” No matter what you call them, these beautiful feathered spirits are worth your own viewing time.
Scientists refer to the Dark-eyed Junco as Junco hyemalis, the latter word from the Latin meaning “of the winter.” That is apt because like so many of our lovely seasonal visitors, these birds are generally found breeding well to the north, across Alaska and northern Canada, while winter generally finds them moving south to warmer climates, or at least to lower elevations. Yet we need to be a bit more precise because the Dark-eyed Juncos are a vexatious species for taxonomists (those scientists who specialize in classifying organisms into logical groups based upon structure, origin, genetics, or behavior).
There are six generally recognized sub-species of dark-eyed juncos in North America, and sources like Wikipedia list as many as 15 different groups. The birds that we see here are almost universally the Slate-colored Junco, named for their dark-gray to black upper coloration. Travel around the continent and you will find other sub-species that vary considerably in color from our own birds: the Pink-sided Junco of the Rocky Mountains (right), the Oregon Junco with a reddish back, the Carolina Junco with yellow wing bars, and so on. Finally, the junco is not a finch, but a member of the sparrow family.
The excellent Stokes Field Guide to the Birds of North America describes the Dark-eyed Junco as follows: a large, deep-chested, broad-necked sparrow with a short, pinkish conical bill, high-rounded crown, and medium-length slightly-notched tail with variable white outer feathers. The bird is roughly six inches long with those bright, jet-black eyes with no eye ring. The guide also recognizes the junco for its tameness when confronted with humans, although not as easy going as the black-capped chickadees in my experience. Juncos have long been popular for scientific studies because they are plentiful, easy to capture and tolerant of handling for measurements, sampling, banding, and installation of tracking devices.
That stocky build, heavily insulated with fluffy feathers, helps these diminutive birds retain critical body heat to survive harsh weather. The short bill allows cracking seeds that form over 50 percent of their diet, especially in the winter when insects are hard to find. Juncos have strong legs, well suited for their foraging by hopping around in brushy thickets or weedy fields. On windy days I often see the juncos hunched tight within thick cover around our house and feeding stations. I take special joy in watching them feed with a bit of snow on the ground because they have a particular habit of kicking their legs out to uncover hidden food, looking for all the world like they are doing the “moonwalk” made famous by Michael Jackson in his Billie Jean video.
Along with many of the grosbeaks, finches, and crossbills, most of the juncos we enjoy show up in the autumn and hang around until springtime. Migration is highly variable among different populations, with some birds staying put all year, while others cover hundreds of miles including long flights over water. Research has shown that adults travel further than juveniles, and females fly further south than males. Migration flights typically occur at night and while weather may play a role in triggering flights, photoperiodism is the dominant factor in bird movements. It seems the juncos fly close to the ground on these long journeys, given the number of dead birds found around tall buildings and television towers.
Staying close to breeding grounds allows males to stake out territories ahead of females showing up in town. Favored nesting sites are in dense conifer stands near open woodlands or fields, since the birds anticipate foraging for food once chicks are born. Males perform courtship displays in hopes of attracting a mate, with both sexes known to sing a long single note trill.
Once paired, the female builds her nest of woven grass, moss, and feathers. Females lay up to five light colored eggs and incubate them for roughly two weeks. The young birds are capable of flight within 12 days but both parents are kept busy finding enough food for the juveniles (left). Scientists have documented some females producing not just two clutches of eggs for the season but as many as five. Predation by chipmunks, deer mice, larger birds, raccoons, skunks, and snakes limits the number of surviving birds.
The Dark-eyed Junco is rarely aggressive, other than when defending its territory or nestlings. They are highly social in nature, often seen in large flocks and mixing with other song birds. I have seen as many as 20 juncos around our feeders, adding color and action to gloomy winter days. They are adaptable to fragmented habitats, readily using parks, housing developments, and harvested woodlands if adequate food supplies are available.
Scientists consider the Dark-eyed Junco a species of least concern, with estimated numbers in North America over 600 million. While their numbers are currently healthy, along with many other song birds the juncos will suffer from continued habitat loss, pollution, and extreme weather events caused by climate change. Our efforts in conservation and the provision of food, water, and shelter to these songbirds are vital to helping them deal with immutable forces around them.
I have no proof that bird watching is allowed in Heaven, but I am willing to wager that my mother and millions of other souls are happily watching their feeding stations while the little snowbirds kick up their heels in the moonwalk!
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