In the spring of 2002, IBP collaborated with National Park Service personnel to conduct an Landbird Inventory of San Juan Island National Historic Park (NHP). Encompassing two disjunct parcels of land called American Camp and English Camp, the park is located on San Juan Island in Washington's Puget Sound.

The Olympic Mountains' rainshadow combines with maritime effects to produce climatic conditions at San Juan Island NHP that are unusual for western Washington. As a result, some of the park's plant communities, including the extensive prairie at American Camp and woodlands at English Camp that include Garry Oak and Rocky Mountain Juniper, are relatively uncommon in western Washington, and host bird communities that are equally atypical for the region.

Representative prairie and forest birds of San Juan Island National Historical Park. (L to R: Savannah Sparrow, Swainson's Thrush, Spotted Towhee, Pacific-slope Flycatcher)

We used variable circular-plot point counts (conducted by IBP intern Heidi Pedersen) to map the distribution of breeding landbirds throughout the park.

Sample map of Spotted Towhee detections across the park.

We then used our point count data to produce habitat-specific estimates of absolute density for the more frequently detected species, and indices of relative abundance for the less frequently detected species. These estimates and indices will serve as baseline data for tracking population changes over time, gauging the effects of any future management actions that may alter habitat conditions in the park, and monitoring future parkwide ecological changes.

View our Final Report for this project.

For more information, please contact Rodney Siegel.

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