There are many landbird species unique to oak and prairie habitats of western Oregon, including Acorn Woodpecker, Blue-gray Gnatcatcher, Bewick’s Wren, California Scrub-Jay, California Towhee, Hutton’s Vireo, Oak Titmouse, Red-shouldered Hawk, White-tailed Kite, and Wrentit. As one of the most conspicuous residents of Oregon’s oak habitats, the Acorn Woodpecker can be an effective catalyst for conservation of this Key Habitat.
Acorn Woodpeckers are visually striking, social birds found in western Oregon’s oak woodlands. Known for their black-and-white plumage and red cap, they rely on oak trees for food and nesting. These woodpeckers store acorns in trees, creating “granaries” that serve as both food storage and breeding sites. They are highly social and often live in groups, working together to protect their acorn caches and raise their young. The Acorn Woodpecker is a year-round resident of oak woodland and savanna habitat in western Oregon, primarily found in the Willamette Valley and Klamath Mountains ecoregions, though occasionally found in the East Cascades.
Acorn Woodpeckers have been expanding their range in Oregon since the arrival of Euro-American settlers, expanding north from Roseburg to Eugene between 1920 and 1950, then further north to Washington County by the early 1990s. Although more than 95% of the oak woodlands have been lost in the Willamette Valley since European settlement, Acorn Woodpecker expansion into the Willamette Valley in the last 100 years was likely assisted by the reduction of fires that maintained grasslands and savanna, transforming some of those habitats into oak woodlands (mixed with pine or fir) that had larger and older trees that produce more acorns and provide more dead limbs for granaries and nests.
Unfortunately, many other landbird species that are associated with oak habitats are experiencing severe population declines. The Partners in Flight (PIF) conservation plan “Population and habitat objectives for landbirds in prairie, oak, and riparian habitats of western Oregon and Washington” examined long-term population trends derived from Breeding Bird Survey data for 33 focal species. Their analysis found that at least 50% of the species in each habitat type (prairie, oak, and riparian) have significantly declining population trends in one or more ecoregions. Several species or subspecies associated with oak and prairie are identified as imperiled by the PIF plan, including SWAP SGCNs: Lewis’s Woodpecker, Oregon Vesper Sparrow, Streaked Horned Lark, Western Bluebird, White-breasted Nuthatch (Slender-billed), and Western Meadowlark. Conservation recommendations included in the PIF plan would also benefit a broad suite of species in decline that rely on oak and prairie habitats.