- Author
- Bob Altman, Avifauna Northwest
- Publication Year
- 2023
- Species
- Streaked horned lark
- Region
- Willamette Valley
- Habitat
- Vernal Pool, Wet Prairie
- Topic
- Birds, Rare Species Recovery, Restoration & Management
- Full Citation
- Altman, B. 2023. Evaluating the Effectiveness of Vernal Pools and Swales in Prairie Restoration for Streaked Horned Larks in the Willamette Valley, Oregon 2022-2023. Unpublished report prepared by Avifauna Northwest for the Institute of Applied Ecology and Oregon Department of Fish and Wildlife. November 2023.
The Streaked Horned Lark (hereafter lark) is an Oregon Conservation Strategy species and a Threatened species under the U. S. Endangered Species Act. Most of its range-wide population (<2,000 birds) occurs in the southern Willamette Valley, Oregon. Larks evolved as an early-successional open landscape-dependent species with a unique niche at the initiation end of the gradient of early-successional habitat. The key features are a large landscape of low-statured herbaceous vegetation with significant areas of sparsely-vegetated and bare ground. This occurs in the Willamette Valley on mostly private agricultural lands, especially grass seed fields, but also anywhere suitable conditions occur such as along the edges of fields, roads, and ditches, and in swales and vernal pools. An essential lark recovery objective is to secure more populations on dedicated conservation lands where habitat management and other conservation actions can be prioritized for them. The two study sites in this project are on former agricultural lands in the southern Willamette Valley where wildlife and prairie habitat restoration are occurring. This includes the creation of vernal pools or the maintenance of existing swales that have the potential to provide lark habitat. However, the effectiveness of these habitats to contribute to lark recovery has not been verified.
The project goal was to assess the effectiveness of created vernal pools and natural swales as lark habitat within the context of habitat restoration at two sites (Erion’s Wetlands and Herbert Farm) over a two-year period (2022-2023). Specific objectives were to:
- document the occurrence and abundance of larks,
- document lark use of vernal pools and swales relative to use of other habitat conditions,
- provide continuity to long-term monitoring at each site, and
- provide recommendations to inform lark recovery strategies.