Riparian landbird monitoring in Golden Gate National Recreation Area and Point Reyes National Seashore: Analysis report through winter 2011-12

Humple, Diana; Porzig, Elizabeth

This document constitutes an analysis and synthesis report for landbird (passerines and near-passerines) monitoring conducted in riparian habitats in Point Reyes National Seashore and Golden Gate National Recreation Area as part of the National Park Service’s Inventory and Monitoring Program, and following protocols established for this purpose (Gardali et al. 2010). Landbird monitoring has been conducted by PRBO Conservation Science (formerly Point Reyes Bird Observatory) at 14 riparian study sites intermittently since 1997, and is conducted annually at a subset of these study sites (“core” study sites). Monitoring was repeated at all sites in 2011, the first year of implementation of the comprehensive protocol. Monitoring methods include point count surveys during the breeding season as well as mist netting during all seasons. Therefore, although 2011 was the first year of implementation of the comprehensive riparian landbird monitoring protocol at the full suite of sites, we were able to produce an analysis and synthesis report because of the historic data that PRBO has been collecting for years at these sites. A separate and complementary progress report provides more information on the monitoring efforts conducted in 2011, including basic summary results and a summary of the activities conducted that year (Jennings and Humple 2014). That information is not repeated herein. One primary objective of this analysis and synthesis report was to identify a list of focal species for use in analyses herein and in future reports. We selected focal species based on a variety of resources, including California Partners in Flight focal species, California Bird Species of Special Concern (Shuford and Gardali 2008), climate change vulnerable species (Gardali et al. 2012), and Palomarin study species; as well as expert opinion and the availability of sufficient data. Twenty-five focal species were selected, including 10 year-round residents, nine Neotropical migrants, five overwintering species, and one passage migrant. The most commonly-detected landbirds when looking at all riparian habitat in the parks combined include the year-round resident Song Sparrow (Melospiza melodia); Neotropical migrants Swainson’s Thrush (Catharus ustulatus), Wilson’s Warbler (Cardellina pusilla), and Allen’s Hummingbird (Selasphorus sasin); and winter migrants Fox Sparrow (Passerella iliaca) and Ruby-crowned Kinglet (Regulus calendula). The patterns in both point count and mist net data over this 11 year period (2001-2011) for these and the other focal species indicate predominantly stable populations. A few species showed trends, including increases (Wilson’s Warbler and Purple Finch, Haemorhous purpureus) and declines (Olive-sided Flycatcher, Contopus cooperi; American Robin, Turdus migratorius; Ruby-crowned Kinglet; and Golden-crowned Sparrow, Zonotrichia atricapilla). A few other patterns were observed in the data although the trends were not statistically significant. The collection of point count and mist netting data continues annually at the core sites, and 2014 is the next year planned for comprehensive point count surveys for the complete suite of study sites, following the protocol’s recommendations to conduct surveys at all sites every three years.

Riparian landbird monitoring in Golden Gate National Recreation Area and Point Reyes National Seashore: Analysis report through winter 2011-12

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