Author: Caitlyn Gillespie

Bird Bio: Pacific-slope Flycatcher
By: Jenna Curtis, KBO Research and Monitoring Intern

Formerly grouped with the Cordilleran Flycatcher as “Western Flycatchers”, the Pacific-slope Flycatcher (Empidonax difficilis) was recognized as a unique species in 1989. Though vocally and morphologically distinct, it is still challenging for many birders to distinguish this species from the visually similar Cordilleran. In fact, the Pacific-slope Flycatcher’s name “difficilis” refers to how difficult it is to separate this species from its more easterly cousin!

The Pacific-slope Flycatcher is a common breeder in low and midelevation forests. This species is often associated with riparian, or streamside habitats, and has been found to prefer mature and old growth forests. Its breeding range extends from southern Alaska to Baja California. In winter, the Pacific-slope Flycatcher migrates to central and western Mexico, where its territories commonly overlap with the Cordilleran Flycatcher.

As the name implies, the Pacific-slope Flycatcher’s diet consists primarily of flying insects, which it catches by “hawking” – flying up to grab insects from a central perch – or by gleaning from leaves and branches. The small size and yellow-green color of this species makes it hard to spot in shady forests. It is more often identified by the high pitched, nasally “Pst-SEET pstick seet!” song given by advertising males. The Pacific-slope Flycatcher is a Partners in Flight stewardship species and is one of the species being monitored by our long-term monitoring program within the Klamath Network National Parks. KBO monitoring data show that the Pacific-slope Flycatcher is the most commonly detected species in Redwood National and State Parks, where it is strongly associated with redwood forests. There are some indications that the Pacific-slope Flycatchers is declining in moist forests of the Pacific Northwest. Continued monitoring and collaborative efforts to conserve the moist,   late-successional forests inhabited by this bird will be needed to maintain healthy Pacific-slope Flycatcher populations.

This article appears in the Summer 2012 Newsletter.

Sources: Marshall, David B. et al, eds. Birds of Oregon: A
General Reference. Corvallis: Oregon State University
Press, 2003.; Lowther, Peter E. 2000. Pacific-slope
Flycatcher (Empidonax difficilis), The Birds of North America
Online (A. Poole, Ed.). Cornell Lab of Ornithology, Ithaca,
NY.; Partners in Flight North American Landbird
Conservation Plan. Cornell Lab of Ornithology, Ithaca, New
York.

By: Liz Williams, KBO Education and Outreach Project Leader

During the breeding season, the Hermit Warbler (Dendroica occidentalis) can be found in coniferous forests along the west coast of Oregon, Washington, and California, in the Cascade mountains of western Oregon and Washington, and in California’s Sierra Nevada mountains. This species winters in montane pine, pine-oak, and cloud forests of Mexico and Central America through Nicaragua. A small, insectivorous warbler, it has a yellow head, white underparts, and gray upperparts. Males have black throats, while females’ throats are grayish, with some black. The species is known to hybridize with Townsend’s Warblers, resulting in birds with plumage characteristics of both species.

The Hermit Warbler is a habitat specialist. During breeding it is most often found in the interior of cool, moist, mature coniferous forests, from sea level into the mountains. It is most abundant in stands over 30 years old, and is not generally found in stands under 20 years old, or in stands that have been extensively thinned. As the Hermit Warbler usually resides high in the canopy, it is more often heard than seen. The male’s variable song is multi-part, consisting of 3 or 4 buzzy notes—“zeegle zeegle zeegle”—; followed by a rising-and-falling ending phrase—“zee-o-seet.”

The Hermit Warbler is a State of the Birds western forest obligate species, meaning that it is dependent on coniferous forest habitats. It is also a Partners in Flight Watchlist Species. Partners in Flight’s Conservation Strategy for Landbirds in Coniferous Forests of Oregon and Washington identifies the Hermit Warbler as a focal species for mature, multi-layered, closed canopy forests. Through improving habitat conditions for Hermit  Warbler, it is thought that other species that depend on older coniferous forest habitats will also benefit.

There is concern that the Hermit Warbler may be declining due to extensive loss of mature forest habitats. The 2011 State of the Birds report indicates that National Forests support 51% of Hermit Warblers breeding in the United States. This high level of stewardship responsibility provides the U.S. Forest Service with a unique opportunity to reverse potential declines in Hermit Warblers through appropriate forest management that will, in turn, improve habitat conditions for a variety of western forest obligate species.

Protecting and restoring the Hermit Warblers’ habitat throughout its breeding range will require collaborations among non-governmental organizations like KBO, the Forest Service, and other public and private forest mangers in Oregon, Washington, and California. Broader collaborations among international partners will also be necessary to ensure connectivity between Hermit
Warblers’ breeding, migratory, and wintering habitats.

This article appears in KBO’s Fall 2011 Newsletter.

Bird Bio: Swainson’s Thrush
By: Robert Frey, KBO Biologist and Banding Project Leader

One of the most commonly heard, although seldom seen, birds of its range is the sedately plumed and melodic songster Swainson’s Thrush. It was named for William John Swainson, a much-accomplished English (and later in life a New Zealander) ornithologist, malacologist, entomologist, and artist. Mr. Swainson has had nine bird species named for him (Swainson’s Francolin, Hawk, Toucan, Fire-eye, Antcatcher, Flycatcher, Thrush, Warbler, and Sparrow).

The western-breeding Catharus ustulatus ustulatus group has a more russet color tone to its upperparts plumage. The boreal- and eastern-breeding C. u. swainsoni group is more brownish-olive. All have pale buffy “spectacles” and sing a wonderful ascending-note, flute-like song.

Swainson’s Thrushes nest across the boreal regions of North America, throughout much of the intermountain west, and along the Pacific Northwest coast.

They are associated with deciduous woodlands and riparian habitats in our region, specifically with a dense shrub layer; a habitat affinity shared by the Wrentit. They are also common in mixed conifer/deciduous forests. Western populations winter in Mexico, while boreal and eastern populations winter southward to Amazonia and further into Argentina’s southern lowlands – some traveler!

Although this species is numerous, with an estimated population of 100,000,000, there is evidence of Pacific Northwest populations declining since 1966. There is also evidence that the Swainson’s Thrush is particularly vulnerable to building strike mortalities, especially during migration.

Interestingly, the root word of Mr. Swainson’s family name, swain, is an Old English term for a male lover or admirer, or a country boy. We can’t say that this suits William John very well, but it may just be a wonderful occurrence of word evolutionary convergence for the sweet-singing son of
swain thrush!

This article can be seen in the Summer 2011 Newsletter.

Sources: Altman, B. 2000. Conservation strategy for landbirds in lowlands and valleys of western Oregon and Washington. PIF; Gruson, E. S. 1972. Words for birds: A lexicon of North American birds with biographical notes. Quadrangle Books, Inc., New York, New York; Marshall et al, eds. 2003. Birds of Oregon: A general reference. Oregon State University Press, Corvallis, Oregon; Rich et al. 2004. Partners in Flight North American Landbird Conservation Plan. Cornell Lab of Ornithology, Ithaca, New York.

By Bob Frey, KBO Biologist and Banding Project Leader

Remember Flower Power – a slogan used as a symbol of passive resistance and non-violent ideology in the 1960s? The Golden-crowned Sparrow (Zonotrichia atricapilla) is a big believer— flowers are very nearly all it eats! Studies have found that plant material makes up 95% to 97% of this songbird’s natural diet, with flowers comprising up to 50% of this.

This large sparrow of the north country nests exclusively in Alaska and western
Canada, on the ground in habitats above the treeline. It is found in western California, Oregon, and Washington only during the winter, spring, and fall seasons. The Golden-crowned Sparrow is a common feeder bird, though preferring to forage on the ground, often flocking with other sparrows. Dark-streaked brown upperparts, light-brownish underparts, a long tail, and a distinctive yellow (golden) crown distinguish it from others in the lowland brush or field edges it frequents. The yellow crown is bordered with dark stripes and is most bright in mature individuals.

The scientific genus name Zonotrichia is Greek for “bird with bands,” an allusion to the crown stripes – from zone for band (or stripe), and trichias for small bird. The species name atricapilla is Latin for “black hairs”, coined from ater or atri for black and capillus for hair, referring to the black bordered crown.

Although there is some evidence of this species increasing in number, there is concern that not enough is known, and that monitoring is insufficient in its northern range—an important challenge for researchers and land managers. The data that KBO collects from Golden-crowned Sparrows captured in the Klamath-Siskiyou Bioregion during the migration and winter seasons contribute greatly to our understanding of this species’ conservation status in North America.

Sources: Marshall et al., eds. 2003. Birds of Oregon: A general reference. Oregon State University Press, Corvallis, Oregon; Gruson 1972. Words for birds: A lexicon of North American birds with biographical notes. Quadrangle Books, Inc., New York, New York; Martin et al. 1951. American wildlife and plants: A guide to wildlife food habits. Dover Publications, Inc., New York, New York; Rich et al. 2004.
Partners in Flight North American Landbird Conservation Plan. Cornell Lab of Ornithology, Ithaca, New York.

This article appears in KBO’s Spring 2011 Newsletter.