North Coast and Cascades Network landbird monitoring: Report for the 2011 field season

Holmgren, Amanda; Wilkerson, Robert; Siegal, Rodney

In 2011, the North Coast and Cascades Network (NCCN) Landbird Monitoring Project continued to follow the comprehensive, field-tested protocol, with two years of annual-panel data collected during the protocol development phase (2005 and 2006), and five years of full project implementation (2007, 2008, 2009, 2010, and 2011) including data collection on the annual panel as well as all of the five alternating panels. In 2011 we conducted 771 point counts at point count survey stations located along 57 transects in the NCCN, including Mount Rainier National Park (MORA), North Cascades National Park Complex (NOCA), and Olympic National Park (OLYM). We faced a challenging year due to extremely late-lingering snow as well as some unexpected communication problems with the crew. We missed more transects than usual at MORA, the direct result of snow but exacerbated by logistics-related problems. We are implementing some procedural changes in 2012 to avoid similar problems in the future. We detected 137 bird species in the three large parks, 94 of which were detected during one or more point counts. For 58 species (all species detected at least 22 times on annual-panel transects between 2005 and 2011), we present the total number of detections on annual-panel transects in each park during the 2005, 2006, 2007, 2008, 2009, 2010, and 2011 field seasons. We caution, however, that these detection totals have not been adjusted for differences in survey effort or potential differences in detectability of birds between years; such adjustments will be made in conjunction with our periodic trend analyses. At San Juan Island National Historical Park (SAJH), we conducted 54 point counts, including 38 at American Camp and 16 at English Camp. Our field crew detected 71 bird species while in the park, 64 of which were detected during point counts. We present the number of detections, and the number of point counts with detections, for each species detected during point counts at SAJH. After the overall increase in the number of birds detected in 2010 in the large parks, 2011 yielded an overall decrease in detections on annual-panel transects. This decrease was in part driven by the decline in evening grosbeak detections at NOCA, dropping from 164 detections in 2010 to 72 detections in 2011. The detection totals of evening grosbeaks in 2011 were relatively consistent with totals prior to 2010. It should also be emphasized that in 2011 we faced the heaviest snowpack since the beginning of our monitoring project in 2005. Closer analyses of the data may indicate concomitant changes in abundance and distribution of some species from previous years as a result of the persistent snowpack and related factors, such as delayed plant phenology and insect activity. In addition, because there were fewer high-elevation transects surveyed at MORA in 2011 than in previous years, fewer birds were detected, which also affected our total number of detections. This was particularly notable for species that we tend to detect in greater numbers at higher elevations, such as pine siskin and dark-eyed junco. The project’s periodic trend analyses will explicitly account for annual variation in survey effort. Preliminary results indicate we will have robust sample sizes for many species when we conduct trend analyses, and that we are detecting substantial year-to-year changes in bird populations. These changes, when analyzed in the context of annual weather variation and perhaps other factors, should yield interesting and useful findings about the drivers of avian population dynamics of Pacific Northwest forests, and are likely to spur additional targeted research and help refine management priorities and needs within these parks.

North Coast and Cascades Network landbird monitoring: Report for the 2011 field season

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