Bird-habitat associations at five national park units in southern Oregon and northern California

Stephens, Jamie; Mohren, Sean; Newell, Felicity; Alexander, John; Sarr, Daniel

As part of the Inventory and Monitoring Program of the National Park Service, the Klamath Network and Klamath Bird Observatory established a protocol to monitor long-term trends in landbird populations at National Park units in southern Oregon and northern California. This report uses data from the first sequence of surveys to examine bird-habitat associations at the five larger park units in the network: Crater Lake National Park, Lassen Volcanic National Park, Lava Beds National Monument, Redwood National and State Parks, and Whiskeytown National Recreation Area. These parks include a diversity of ecosystems from high elevation coniferous forest to shrub-steppe, temperate rainforest, chaparral, and oak woodlands. At each park 25–35 sites were established using a stratified random approach that consisted of 3 designated sampling frames. Breeding season point counts were conducted at each park from 2008–2010, along with collection of vegetation data. For this analysis we estimated breeding density of 39 bird species (8–16 species per park) in Program DISTANCE. We used a model selection approach to compare the influence of different habitat features on bird density at each park, including topography, vegetation structure, and floristics. For species occurring at several parks, we examined similarity of associations across parks. Densities of individual bird species were related to a range of factors including elevation and habitat features important for foraging and nest sites. For example, across parks Mountain Chickadees (Poecile gambeli) were less abundant at high elevation subalpine sites, Brown Creepers (Certhia americana) were associated with snags which are used for both nesting and foraging, and Wilson’s Warblers (Cardellina pusilla) were associated with shrub cover in riparian areas. Several bird species showed strong floristic preferences, and were found in specific plant communities within the park. For example Black-throated Gray Warblers (Setophaga nigrescens) were associated with canyon live oak (Quercus chrysolepis) at Whiskeytown National Recreation Area. Results support information on bird-habitat associations in the region and are presented in the context of park management and Partner’s in Flight conservation objectives.

Bird-habitat associations at five national park units in southern Oregon and northern California

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