Neighborhood Naturalist, Spring 2017 by Neighborhood Naturalist

neighborhood naturalist CORVALLIS, OREGON — SPRING 2017

Lesser Goldfinch article and photography by Lisa Millbank

he Lesser Goldfinch is essentially a Southwestern bird, at home in open pine-oak woodlands and rolling foothill rangelands. Few nineteenth-century ornithologists documenting Oregon’s birds reported Lesser Goldfinches, so they may be relative newcomers to the Northwest. Bird feeders, irrigation and development may have enabled these tiny finches to expand their range northward to Washington. On the other hand, it’s possible that Lesser Goldfinches were always in Oregon, but were overlooked by most early naturalists. Distinguishing them from American Goldfinches isn’t always easy. The two color patterns of adult males—“black-backed” in the eastern part of their range, and “green-backed” in the West—might have confused things further. An adult male Lesser Goldfinch from our area has a black cap, olive back and yellow underparts. His black wings and tail are marked with white patches. His American Goldfinch counterpart has two adult male plumages, bold yellow and black for the breeding season, and a much more subdued look for fall and winter. Females and juveniles of both species, as well as nonbreeding male American Goldfinches, are all similar in appearance.

and the presence or absence of a white patch on the wings usually is sufficient to identify them. Perhaps the easiest way to tell them apart is by listening to their calls. The Lesser Goldfinch gives a rough chig-chig-chig call and a variety of sweet, plaintive notes often described as “kitten-like” in field guides. Both goldfinch species are excellent singers, but the male Lesser Goldfinch has a hidden talent that most birders don’t know about: he’s a mimic, incorporating the sounds of other birds into his own song. But don’t expect to hear him caroling like an American Robin, or giving the rich warbling song of a Purple Finch. Instead, he selects halfsecond “clips” of bird sounds, compresses them into a rapidfire mashup of call and song fragments, and delivers them so quickly that it’s hard to perceive what he’s imitating. A single male can imitate dozens of species.

Certain bird sounds appeal to Lesser Goldfinches, such as the killy-killy-killy of the American Kestrel, the pee-er of the Western Wood-Pewee, the pit-a-tik of the Western Tanager, and the keeer of the Northern Flicker. A Lesser Goldfinch may also mimic the calls of his close relatives, the American Goldfinch and the Pine Siskin. Most of these are loud, simple calls that the Lesser Goldfinch hears in his open woodland habitat. The function of the Lesser Despite the Lesser Goldfinch being noticeably smaller, Goldfinch’s mimicry isn’t well understood, but a male with it’s often other field marks that help birders tell the two a large repertoire of song imitations is likely signaling his apart. Noting the wing bars, color of the undertail coverts superior fitness in some way. Neighborhood Naturalist, Spring 2017 v15 #1 • page 1

The large white patches on the wings and tail are unique to the adult male Lesser Goldfinch.

Similarly, the adult female Lesser Goldfinch has white wing patches, but they’re smaller than the male’s.

The long, rambling songs usually contain three elements: a mixture of call notes, imitations of other species, and phrases that seem unique to Lesser Goldfinches. To our ears, the song may seem random and jumbled, but the different elements are combined in specific ways, beginning with call notes and consisting of about 50% imitations.

Goldfinch perched on a bird feeder, fluttering her wings and begging like a fledgling toward her mate. He then regurgitates seeds into her bill. Though the female is fully capable of feeding herself, courtship-feeding plays a role in pair-bonding and preparing the birds for their roles in the nesting process. The female will depend on the male to feed her while she incubates, and she also requires extra food during egg-laying.

Watch a video and listen to the sounds of Lesser Goldfinches www.neighborhood-naturalist.com

During the courtship and nesting period, the male Lesser Goldfinch puts on exuberant displays that show off his singing ability, flight skills and colorful plumage. By late February, males are singing frequently, and pairs Bounding through the air with exaggerated wingbeats, he begin to form as winter fades into spring. The male follows flies in a wide circle, singing loudly. He flashes his white the female when she flies, and eventually they engage in wing and tail patches, and his yellow underparts glow in high-speed chases through the trees. In quieter moments, the sunshine. These “song flights” may advertise ownership the birds touch their bills together while perched side-by- of his nesting territory. However, territorial behavior in the side. highly sociable goldfinches seems more casual than it is for many other birds, and multiple pairs of Lesser Goldfinches In early spring, it’s common to see an adult female Lesser have been observed nesting relatively close together.

Being a small, lightweight bird has its advantages. They are able to access seeds on thin twigs like these alder cones.

The seeds from thistles and many other plants are the Lesser Goldfinch’s staple foods.

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American Goldfinch

Lesser Goldfinch

Adult male in breeding plumage. American Goldfinches molt twice a year, alternating between yellow and dull olive-brown.

Adult male. Lesser Goldfinches molt once a year. Once they become adults, they look the same for the rest of their lives.

Adult female in breeding plumage. She has wider wing bars, pink legs, an orange bill and white under her tail.

Adult female. Note her thin wing bars, small white patch at the base of her primaries, dark legs and bill, and yellow under her tail.

Non-breeding adult. Sexes similar, but male often has more yellow. Has wide wing bars, dark bill, and is white under tail.

Immature male. His black cap is not yet complete. The white wing patch is apparent, and not present in the American Goldfinch.

American Goldfinches are notable for their late breeding lining, usually of cottonwood or willow fluff, and may also season, which doesnâ&#x20AC;&#x2122;t begin until late June or July. But the use spider webs and silken cocoons. Lesser Goldfinch starts nesting about the same time as most other songbirds, in April or May. She lays 4-5 pale blue eggs, and they hatch in about 1213 days. Insects are the primary food for almost all songbird The female Lesser Goldfinch chooses a nest site in the chicks, but like other finches, Lesser Goldfinches feed their dense foliage of a shrub or tree. With little help from the babies a near-vegetarian diet of moistened, regurgitated male, she builds a tightly-woven nest with grasses, lichens, seeds, with only small numbers of aphids and other insects. plant fibers and bark, forming a neat cup. She adds a soft Neighborhood Naturalist, Spring 2017 v15 #1 â&#x20AC;˘ page 3

Illustration by Don Boucher

This female is collecting willow fluff to line her nest. The 3-inch-wide nest is a tightly woven structure made of fine grass or other plant fibers, and lined with plant down. The Lesser Goldfinch nests in trees and shrubs, concealed by leaves and branches.

Most songbirds wait until they have laid the full clutch before incubating so the chicks’ hatching is synchronized. But the Lesser Goldfinch starts incubating before completion of the clutch, so there may be chicks whose ages are several days apart in the same nest. Nevertheless, all of the chicks fledge as a group about two weeks after hatching. The parents feed the fledglings for several weeks, and several family groups may flock together as the young birds become more independent.

and thistles, are their favorites. Gardeners have a good excuse to let some dandelions or a lettuce crop go to seed— tiny seeds like these attract Lesser Goldfinches. They also like the seeds of Lemon Balm and other mints.

Some sparrows and finches like to nibble tender green vegetation, but Lesser Goldfinches can do this to such an extent that they injure cultivated garden plants. A Lesser Goldfinch will land on a chard leaf and tear out pieces on either side of the midrib, or perforate sunflower leaves In some years, most Lesser Goldfinches leave the between the veins. Gardeners can keep them away from northernmost parts of their range as the weather gets certain plants with netting or floating row covers, but Lesser colder. In the mid-Willamette Valley, many are year-round Goldfinches are such enjoyable garden visitors that they residents that endure the dark, damp winters. Many of these more than make up for holes in a few leaves. overwintering birds visit bird feeders regularly. They prefer black oil sunflower seed, sunflower seed chips or Niger seed Take note the next time you see a flock of goldfinches at (also sold as nyjer or thistle seed). the feeder or in the garden. With a little practice and care, you can sort out the Lessers from American Goldfinches. When they’re not at feeders, Lesser Goldfinches forage Watch for a male’s display flight, and listen for his quick for all kinds of seeds, buds, flowers, fruit and even leaves. imitations of other birds. The smallest of finches puts on The seeds of composite flowers, such as sunflowers, zinnias an outsized performance! ó

Lesser Goldfinches nibble on fresh greens, like this naughty one with the evidence on her bill. Chard leaves are particular favorites. Neighborhood Naturalist, Spring 2017 v15 #1 • page 4

Coralroots article and illustrations by Don Boucher, photography by Lisa Millbank

hile hiking in the forest this spring, you might come across a shady spot with sparse vegetation on the ground. A cluster of foothigh, bronze-colored stalks bear tiny, white petals with garnet spots. Upon a closer look, there are only the flower stalks—there are no leaves that seem to belong to the plant. There are some dead stalks nearby, apparently from last year, but no green whatsoever. This is Spotted Coralroot, and along with the similarlooking Western and Striped Coralroots, it’s one of three coralroot species in our forest. They’re oddballs among our spring flowers. Consider some milestones in plant evolution such as photosynthesis, the development of vascular tissue (which made roots as we know them possible), the emergence of seeds, and reproduction through flowers. While these adaptations have led some plants to dominate, coralroots have instead forgone photosynthesis, lost their functional roots, and their seeds resemble the spores of more primitive plants, both in size and habit. They have retained the ability to reproduce with a lovely raceme of flowers. Botanists had long assumed that coralroots got their sustenance from digesting dead plant matter. It turns out that plants do not directly contribute to the breakdown of dead plants. Biodegradation is largely carried out by bacteria and fungi because they can produce the necessary enzymes to break down plant fibers. Instead of deriving their energy from digesting dead plants or photosynthesis, coralroots are fungal parasites, or mycoheterotrophs. A coralroot appears above the soil surface only as a flower stalk, and the structure dies when the seeds are ripe. The permanent parts of a coralroot are the subterranean rhizome (which is a stem, not a true root) and the bulblike base of the flower stalk. Without roots and root hairs, the plant can’t absorb water and nutrients from the soil. Instead, the rhizome is enveloped in a fungal coating. This parasitized fungus is connected to a network of fungal threads, which does the work of gathering nutrients and water. To maximize exposure to the fungus, the coralroot rhizome has a branched structure with many evenly-spaced protuberances, resembling some corals. Frequent hosts of coralroots are fungi in the family

Spotted Coralroot

Russulaceae. Some species produce familiar fall mushrooms in our forests, including very large white mushrooms and others with red, yellow or brown caps. Striped Coralroot also targets certain crust fungi that appear on rotting wood. When they’re not visible as mushrooms or crusts, these fungi remain in the soil as an extensive network of microscopic threads called hyphae. Together, the hyphae form the fungal mycelium, which is connected to the roots of trees or other plants in a symbiotic relationship. This symbiosis, called a mycorrhizal network, boosts the productivity of the forest ecosystem. The fungi help plants gather water and minerals, while the plants produce carbohydrates for the fungi. But coralroots cheat the system by stealing sugars, minerals and water from the network and giving nothing back. Coralroots are in the orchid family. While their blossoms aren’t very large, they still have the fancy bilaterallysymmetric structure of familiar cultivated orchids. It’s well-known that many orchid species have elaborate and exclusive relationships with specific pollinators. There isn’t much research on which pollinators might visit our

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early fall, the capsules open and the seeds come wafting out. Orchids produce thousands, sometimes millions, of dust-like seeds. A typical seed from any other plant family is larger because it includes an endosperm. The endosperm provides nutrients and energy to the embryo to grow the young plantâ&#x20AC;&#x2122;s first roots and leaves. In some ways, orchid seeds resemble spores in that they are small enough to be dispersed by wind, and they depend on tenuous conditions to germinate. Unlike spore-bearing plants, like Coralroot seeds are very small and light, but are actually large for ferns and mosses, orchid seeds contain an embryo, which orchid seeds. A single plant disperses thousands of seeds to the wind. is a genetically complete version of the next generation. By contrast, spore-bearing plants must go through an coralroots, and no documentation on Western Coralroot. additional reproductive process, after the spore germinates, Researchers have discovered that Striped Coralroot is to produce an embryo. pollinated by the parasitoid wasp Pimpla pedalis. In addition to pollination by insects, Spotted Coralroot is Without the benefit of an endosperm, an orchid capable of self-pollination. seed must happen upon its fungal host, and under the right conditions, so that the seed can absorb energy and Once pollinated, the ovaries at the base of the blossoms nutrients. The orchid seed must first end up in a spot with develop into oval seed capsules. The seeds mature as the sufficient moisture. Then, appropriate fungal hosts must be flower stalk dies and desiccates. Later in the summer or present, and the fungal hyphae must happen to penetrate

The Subterranean Life of a Coralroot coralroot flowering stalk

coralroot rhizome

plant roots

roots and fungus are connected symbiotically

coralroot parasitizing fungus

mycelium forms mushrooms in fall

fungal mycelium The coralroot gets its name from the coral-shaped rhizome and is coated in a layer of fungus. These species of fungus (depicted here as a fall Russula mushroom) have mycelia that are symbiotically connected to plant roots. This plant root and mycelium network share water, sugars, and minerals. The coralroot attracts the fungus, draws in nutrients and water, but gives nothing in return.

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Striped Coralroot

Western Coralroot

Spotted Coralroot

Conifer forests in the Coast Range foothills, Cascades, and occasionally in the Willamette Valley. 6 to 20 inches. Purple or dark magenta stems. The petals are large and cream-colored with magenta stripes.

Conifer or mixed forests. Most common in the Cascades; uncommon at higher elevations in the Coast Range. 6 to 20 inches. Pink stems. The blossoms have narrow, brown petals except for the pink lip.

Conifer or mixed forests in the Coast Range, foothills and Cascades. 8 to 20 inches. Characterized by the lower petal (or lip) that is white with magenta spots. Otherwise the stem and other petals are reddish to bronze.

Corallorhiza striata

Corallorhiza mertensiana

the seed covering. But this is not yet enough to induce germination. If the orchid seed is successful, the fungus will allow the embryo to absorb nutrients. All orchids at this stage of germination are fungal parasites. But sometimes, the fungus will kill the embryo. As a side note, commercial orchid growers avoid this unlikely fungal happenstance and instead germinate orchid seeds on a nutrient-rich agar medium.

Corallorhiza maculata

trace amounts of chlorophyll. The coralroot continues to attract the fungus to its rhizome tissues, but also controls its growth with an antifungal chemical called orchinol. As the rhizome grows, it stores energy, and during some future spring, it will grow a flower stalk.

Even if coralroots are parasites, they arenâ&#x20AC;&#x2122;t regarded by ecologists as pathogens that threaten forests. In fact, coralroots themselves face threats since they rely on Many orchids continue some kind of relationship extraordinary conditions to grow. While our coralroot with fungi as mature plants, but also have leaves that species are doing well, some species outside our region are photosynthesize. Our coralroots stay totally dependent on rare and threatened. fungi because they have only minute, vestigial leaves and Neighborhood Naturalist, Spring 2017 v15 #1 â&#x20AC;˘ page 7

Keep an eye out for coralroots this spring and, if you find some, see if you can identify the species. Take note of where you found them in the spring and return in late summer or early fall. The dried, brown flower stalks are

easy to overlook, so you might even mark the spot with a stick or other natural materials at hand. You can shake the capsules into your hand to get a look at the wispy seeds. ó

Other non-green plants in Western Oregon 1

1) Phantom Orchid (Orchid family) Fungal parasite. Shady conifer forests with little or no vegetation on the forest floor. 2) Pinesap (Heath family) Fungal parasite. Shady forests, more common at mid- to high elevations. 3) Indian Pipe (Heath family) Fungal parasite. Shady forests from low elevations to the mountains.

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4) Broomrape (Broomrape family) Plant parasites. Several species. Uncommon in meadows at low to mid-elevations, mostly in the Cascades or Siskiyous. 5) Candystick (Heath family) Fungal parasite. Uncommon in conifer forests, mostly in the Cascades. 6) Pinedrops (Heath family) Fungal parasite. Forested areas in the Cascades. 7) Dodder (Morning glory family) Plant parasites. Four species; uncommon. Low elevations.

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