- Author
- Altman, B.
- Publication Year
- 2024
- Species
- Oregon vesper sparrow
- Region
- Willamette Valley
- Habitat
- Upland Prairie
- Topic
- Birds, Monitoring
- Full Citation
- Altman, B. 2024. An assessment of population status, limiting factors, and conservation actions for an Oregon Vesper Sparrow metapopulation in the Willamette Valley, Oregon, 2016-2023. Avifauna Northwest unpublished report to American Bird Conservancy. January 2024.
Oregon Vesper Sparrow is one of the most imperiled birds in North America. It has been designated as a bird of high conservation concern and vulnerability by all natural resource entities within its breeding and wintering range and is currently being reviewed by the U.S. Fish and Wildlife Service for listing under the Endangered Species Act. A range-wide inventory, anecdotal reports, and intensive demographic research in three ecoregions within its range suggest that the remaining population is approximately 3,000 birds. Breeding Bird Survey data indicates a statistically significant declining population trend of 3.2% per year.
This report summarizes data collected in 2016-2023 to assess population status and potential limiting factors and recommend conservation actions for an Oregon Vesper Sparrow metapopulation in the Willamette Valley, Oregon. Study design emphasized an examination of multiple metrics within three demographic vital rates (i.e., productivity, survival, dispersal), and among several habitat types and land uses. Additional components included habitat assessment to evaluate the role of vegetative composition and structure on nest-site selection and nest success, artificial conspecific attraction in 2020-2021 to solicit colonization of unoccupied sites, and archival GPS tags attached to birds in 2022 and retrieved in 2023 to assess migratory routes and wintering locations.