Identification:
What is an Oregon Vesper Sparrow?

Oregon Vesper Sparrows (Pooecetes gramineus affinis) are a subspecies of vesper sparrow found in the western parts of southern British Columbia through the Puget trough and Willamette Valley. Oregon vesper sparrows are found west of the Cascades, inhabiting the prairie oak habitats scattered throughout the region. They favor open, sparsely vegetated areas with a mix of bare ground with grasses and forbs for nesting and foraging, and scattered taller shrubs or trees for perching and singing.

Oregon vesper sparrows are small cryptically colored sparrows with secretive habits. Oregon vesper sparrows are most likely of the other local grassland sparrows to sing from the ground, though they typically choose a prominent perch in their territory. Female Oregon vesper sparrows lay 3-5 eggs in nests on the ground tucked into a host plant, usually a bunchgrass. Females handle nest building and incubation, and both adults feed nestlings and young until they are independent and capable of feeding themselves.

Why are there so many subspecies unique to Garry oak woodland and prairie habitats in western Washington and Oregon? Learn more about the the ancient glacial legacy of the Puget Sound reflected in the at-risk subspecies found here.

Oregon vesper sparrow at Joint Base Lewis-McChord (Charlie Wright 2024)

Oregon vesper sparrow adult (Illustration by Marissa Gibson 2025)

English Name: Oregon vesper sparrow

Scientific Name: Pooecetes gramineus affini

Status: Candidate for federal listing | Threatened (WA) | Threatened (OR)

  • Grayish brown above with dark streaks on white breast and face, white outer tail feathers.
  • Solid white eyering and pale malar stripe contrasting dark cheek marking.
  • Rufous shoulder patch, often obscured by body feathers.
  • Male and female identical.

  • Oregon vesper sparrow songs start with two introductory notes “schew scheew” that are followed by 3 descending repeated warbling phrases.

  • Males sing and defend territory.
  • Females build a nest on the ground, sheltered by a host plant, where they lay 3-5 eggs.
  • Nestlings fledge after 9 days in the nest while still flightless; they depend on both parents for food for several weeks after fledging until they are independent.

 

Range map of Oregon vesper sparrows in Washington state (WDFW)

Did you know? Oregon vesper sparrows migrate as far south as Baja California where they join other subspecies of vesper sparrows during the winter months.