Neighborhood Naturalist Winter 2017-18

neighborhood naturalist CORVALLIS, OREGON — WINTER 2017-18

Dark-eyed Junco article and photography by Lisa Millbank

U feeders.

biquitous and approachable, juncos sing from subalpine meadows, flit through dark conifer forests, and peck at millet under backyard bird

I remember watching them in my grandmother’s yard, as I paged through her old field guide from the 1960s. One of the color plates depicted several junco species: Slatecolored, White-winged, Gray-Headed and Mexican Juncos, and our version, the Oregon Junco. My grandmother’s hairdresser called them “executioner birds” because of their dark hoods.

It seemed pretty straightforward—each species of junco was distinctive in color and pattern. But in 1983, most of the birds on that page were rolled into a single species, the Dark-eyed Junco. This was because scientists had observed different junco types interbreeding in small zones where their ranges overlapped. The Mexican Junco and some other very similar-looking juncos became the Yellow-eyed Junco.

While juncos have always been popular research subjects for ornithologists, the recent advances in rapid DNA sequencing have taken these studies to a new level of sophistication. This commonplace little sparrow is the focus of cutting-edge genetic studies that not only challenge the current taxonomy of juncos, but also defy long-held assumptions about evolutionary change.

The story of the Dark-eyed Junco and all its varied forms begins in the highlands of Mexico during the Last Glacial Maximum. At the end of the Pleistocene, Mexico had a more temperate climate, and a species of junco with yellow eyes thrived there. As the climate began to warm and vegetation patterns shifted, some of these juncos expanded their range northward. The earliest forms of the Dark-eyed Junco arose from this northern population somewhere around what is now the southwestern United States.

Pioneering populations of this young species continued northward as the ice sheets retreated, and some populations became isolated geographically from one another. For

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reasons that are not yet clear, the juncos rapidly diversified into the forms we know today.

Juncos challenge the notion that speciation must always occur over very long time scales, i.e., hundreds of thousands or millions of years. The DNA of modern juncos reveals that Dark-eyed Juncos split off from their yellow-eyed ancestors only about 10,000-20,000 years ago. Although they are still very similar genetically, the various forms of Dark-eyed Juncos may be on the path to full speciation and reproductive isolation from one another.

While watching juncos in the back yard, it’s hard to believe that they’ve only existed in their current form for such a short time. They’re adaptable and hardy, and those traits allowed them to survive almost everywhere in North This female collects fine grasses for her nest lining. Her mate keeps America. watch and sings from a nearby branch.

Dark-eyed Juncos of the Oregon group are present locally year-round, but many of the overwintering birds are not the same as the locally breeding individuals. Some of them are altitudinal migrants, descending from the higher elevations of the Cascades and Coast Range for the winter. Others may come from as far north as coastal Yukon to spend the winter in our milder climate, while some of the juncos breeding locally may travel southward for the winter.

Numbers of Dark-eyed Juncos in Willamette Valley neighborhoods increase dramatically sometime in October or early November. They’re highly sociable birds, and prefer to stay in small flocks through the nonbreeding season.

This nest is built into a cavity in a small roadcut.

Telling the difference between males and females isn’t as straightforward as it looks in the field guides. Typically, adult males have the blackest hoods, while females’ hoods tend to be grayer. However, there are intermediate birds whose sex can only be determined if the bird is captured and examined. Immature birds are generally the palest in color. Males average slightly larger than females, with longer wings and more white in the tail.

At feeding areas, male Dark-eyed Juncos assert their dominance over females, and older juncos also dominate younger birds of the same sex. The intensity of the contrast between the light bill and the dark hood of adult birds, as well as the physical size of the individual, seem to be visual cues of dominance. Most of their dominant behavior amounts to quick scuffles over the best place to feed, and when there is ample food, juncos feed together in relative peace.

The female places the grass into the nest, and then presses her body into the cup to shape it.

Their slightly larger body size gives males a small advantage over females in colder climates. During fall

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migration, female Dark-eyed Juncos tend to migrate farther south than males, leading to skewed sex ratios in many winter flocks. A study done in Corvallis showed 2.8 males to every female, and the difference in body size is thought to be the biggest factor.

In the winter, Dark-eyed Juncos search the ground for tiny seeds, showing a preference for seeds 1 mm or less in diameter. Hard seeds are broken down mechanically in the gizzard with the sand and grit they frequently ingest.

Though they’re primarily seed-eaters, juncos also eat insects, spiders and fruit. Nestlings are fed insects, sometimes mixed

Dark-eyed Juncos in Western Oregon

Adult male

Adult female or immature

Oregon Junco Our standard junco with a gray to black hood, brown back and buffy flanks. Hood color ranges from black to light gray, sometimes with brown. Adult males, adult females and immature juncos vary in hood color, though a deep black hood usually indicates an adult male.

Slate-colored Junco

Cassiar Junco

This form of Dark-eyed Junco is an uncommon winter visitor to the Willamette Valley. The even gray color of the hood blends almost seamlessly with the gray flanks. On the breast, the bottom edge of the hood has a different shape, when compared to the Oregon Junco. Females and immature birds often show some brown.

Some wintering Dark-eyed Juncos have characteristics of both the Oregon and the Slate-colored types. Cassiar Juncos are still regarded as their own separate subspecies within the Slatecolored group, but they may instead represent Oregon x Slatecolored hybrids. They’re variable, but they usually show a darker hood than the rest of the body color, and have gray flanks.

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with seed or grit. Dark-eyed Juncos are especially fond of white millet scattered on the ground, but will also come to platform-type bird feeders.

As the days lengthen, the males begin to sing their simple musical trills, which vary in tempo, length and pitch.

Compared to the wrens, thrushes and finches, the junco’s song is simple in structure, but each male has a repertoire of variations. In patchy forests, the Orange-crowned Warbler and Chipping Sparrow sing similar trilled songs.

Fledglings are streaked with brown and lack a dark hood.

This late-summer youngster is molting out of its streaky pattern.

Both males and females give the same basic call notes, but they also sing a short-range song—a remarkably complex but quiet series of trills, warbles and other notes.

No one really knows the significance of this song type, but it may be involved in pair-bond maintenance or to prepare the female to begin ovulating.

Female juncos usually build their nests in small hollows under logs or roots, tucked under a fern, or even in old robin nests. It’s extremely rare for a junco to use a nest box, though it has been documented. The nest is a tidy cup, begun with a ring of coarse twigs or leaves, then lined with progressively finer materials, such as grasses, hair, mosses and small roots. The eggs are white with brown speckles, and a typical clutch contains 3-5 eggs.

It’s a real challenge to find a Dark-eyed Junco’s nest, and the incubating mother and nestlings are well-concealed from most aerial predators. But a nest placed at or near ground-level has other vulnerabilities. Weasels, skunks, opossums, mice and chipmunks can prey on eggs or young, and suburban-nesting juncos suffer heavy predation by domestic cats—another reason to keep cats indoors.

I’ve also seen a nest that was partially destroyed when a homeowner was mowing the lawn; the mower was pushed under an overhanging shrub and hit the unseen nest.

The babies grow quickly on their diet of insects, and they leave the nest only 9-12 days after hatching—well before their wings and tail are fully grown. The young birds scatter and hide in vegetation, staying motionless, but they beg quietly so their parents can find them and deliver food.

As their plumage grows in, they look like another species altogether. Patterned with fine brown streaks and no hint of a dark hood, they look much like some of our other juvenile native sparrows. Their conspicuous white outer tail feathers make identifying them easier, until they acquire the more typical junco pattern during the late summer molt.

Adults have the characteristic dark hood and no streaking.

Scientists have thoroughly researched the reproductive cycle of Dark-eyed Juncos, in part because they’re easy to observe, they do well in captivity, and they’re common continent-wide. One of the best-known studies involved

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researchers manipulating the testosterone levels of breeding male juncos, and observing the effect that this had on their reproductive success. Those males whose testosterone levels were artificially raised were able to control larger territories than the males in the control group. And while male juncos are usually fairly monogamous, the experimental group with increased testosterone sought out many more extrapair matings with neighboring females. Thus, they fathered more young than the control group males.

However, there was a cost to the experimental juncos.

The testosterone increase was associated with a sharp decrease in paternal care, and therefore, the control group’s young were ultimately more successful. Not surprisingly, the testosterone levels of an average male are probably at a level that balances the necessary aggressive territorial and sexual behavior against good paternal care. This research on juncos helped scientists understand how male sex hormone levels affect the fitness of individual birds and their offspring.

Winter flocks of Dark-eyed Juncos are so common and familiar that they’re often overlooked by birders. Learning their story has given me a new appreciation for the flock hopping around on our patio. I remember that not all that long ago, on an evolutionary scale, what I’m seeing today A male singing in springtime. Some females may resemble males, didn’t exist. We can only wonder how they’ll change over but the loud trilled song is a male behavior. the next few millennia. ó

This junco is crouching deep in the grass and remaining still until a perceived threat has passed.

Watch the Ordinary Extraordinary Junco documentary at http://juncoproject.org

If not eating backyard bird seed or insects, juncos eat many kinds of wild seeds, like the tiny seeds of this lemon balm plant.

Watch a short video and listen to the sounds of the Dark-eyed Junco at www.neighborhood-naturalist.com

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Snow Queen

article and illustrations by Don Boucher, photography by Lisa Millbank

W

inter seemed like a fresh novelty during the winter holidays, but by now, winter is more like a tedious reality. Don’t let that bother you.

Somewhere under dark, drippy conifers, and soggy, mossy Bigleaf Maples, Snow Queen offers little dabs of color to brighten dreary days.

Snow Queen (Synthyris reniformis) is common, but not always easy to spot because it’s only a few inches high. It can be found throughout western Oregon and Washington, and northern California. It’s a hardy plant of moist, shady forests, from the lowlands to as high as 6,000 feet. On the coast, it can be found near sea level. Inland, it’s most common from a few hundred to 4,000 feet. It survives Is it too early to tease you with a spring wildflower? heavy frosts and can bounce back after being covered in No, because Snow Queen blossoms can easily be found snow. The plant also goes by the name Spring Queen, in February and it’s possible to find outliers that bloom in perhaps more suitable for our mild climate.

January or even December. Not only is it an early bloomer, the blooming period is also long, with some flowers lasting Being small isn’t altogether a disadvantage. At least through June. during the earlier part of its blooming period, it has nearly Neighborhood Naturalist, Winter 2017-18 v15 #4 • page 6

exclusive access to early-season pollinators, because there aren’t any larger, showy flowers to compete with.

Synthyris reniformis was named by David Douglas, a nineteenth-century botanist and explorer, who documented the plant in the Columbia Gorge. The genus name Synthyris means “fused valve” and describes the plant’s seed capsules (see illustration of the S. reniformis capsule on page 8).

In some books, this little plant may be called Kittentails, although there’s nothing very kitten-like about it. The name comes from closely related plants in both the Synthyris and Besseya genera, because they have flower stalks that are tall, densely-flowered, and fuzzy. These vaguely resemble the raised tail of a kitten, if you use your imagination.

Synthyris is in the Plantaginaceae family, which includes snapdragons, foxglove, penstemons, speedwells, plantains (members of the Plantago genus, not the bananas!), and some aquatic genera. The genus Synthyris was formerly in the family Scrophulariaceae, and you’ll find it listed this way in older field guides.

Among its relatives, Snow Queen is the most common species in Oregon, and the only one you’ll find locally. In the Columbia Gorge, where there are popular hiking trails, Columbia Kittentails (S. missurica var. stellata) may offer

In winter, the underside of leaves may have a deep burgundy color between the veins, and sometimes the color covers the entire underside.

The tiny flowers occur in loose clusters. The petals vary in color, depending on the plant, and are lavender or almost powdery blue.

The two stamens extend beyond the petals and add little specks of saturated purple color to each flower.

The leaves are heart-shaped with shallow lobes and fine, jagged margins. Leaves and flowers are borne on separate stems, and are sparsely covered in fine, short hairs. Older leaves have reddish colors between the veins.

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the most common identification challenge. Although the flowers themselves look very similar, the flower stalk is much taller and has a dense spike of flowers (see the illustration of Columbia Kittentails below). In southwest Oregon grows Heart Leaf Snow Queen (S. cordata); it’s closely related to our local Snow Queen, but its narrower leaves distinguish it. A small population of Fringed Kittentails (S. schizantha) occurs in the northern Coast Range in Clatsop County.

This uncommon wildflower has sharply-toothed leaves and a tall flower spike bearing blossoms with deeply incised, fringe-like petals.

Outside of Snow Queen’s range in Oregon, there are two others in the genus Synthyris, also denizens of shady, forested habitats. Mountain Kittentails (S. missurica var. missurica) grows in the mountains of northeast Oregon, and looks similar to Columbia Kittentails. Red Kittentails (S. rubra) has a tall fuzzy stalk with red flowers, and grows in the mountains of south-central and northeast Oregon.

Spring leaves are a fresh green color. At the top of the photo, a small brown moth takes nectar from between the petals of a blossom.

Snow Queen is hardy and easy to grow in a garden, and it will thrive on the north side of your house or in the shade of dense conifers. It grows best in rich, well-drained humus—fitting for a little plant of deep forest soils. Though it prefers to have some moisture during the summer, established plants are drought-tolerant and need little care.

You can find Snow Queen at some native plant nurseries.

During your next winter hike, slow down a little and scan the forest floor along the trailside. Perhaps in a sunbeam between Bigleaf Maples and Douglas-Firs, you may discover the small 7 mm but enduring beauty of Snow Queen. ó The seed capsules are heartshaped and somewhat flat, with either side housing a chamber of seeds.

Columbia Kittentails is found in the Columbia Gorge. It looks similar to Snow Queen, but has a taller flower stalk with more flowers that are densely packed together.

Neighborhood Naturalist promotes interest about nature in mid-Willamette Valley backyards, neighborhoods, and countryside.

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