North Coast and Cascades Network landbird monitoring: Report for the 2020 field season
Holmgren AL , Wilkerson RL, Siegel RB, Ransom JI. 2021. North Coast and Cascades Network landbird monitoring: Report for the 2020 field season. Natural Resource Data Series. NPS/NCCN/NRDS—2021/1337. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/nrr-2288211
In 2020 the North Coast and Cascades Network (NCCN) continued to implement the Network’s Landbird Monitoring Protocol, in partnership with The Institute for Bird Populations. The protocol was initially field-tested with data collected from the annual panel only, as part of protocol development during 2005–2006, and has subsequently been implemented fully (including data collection on the annual panel as well as all of the five alternating panels) for the past 13 years (2007–2020), except for 2017 when data collection was temporarily suspended to reallocate resources for a 5-year data synthesis. In 2020 we conducted 1,180 point counts at point count survey stations along 68 transects in the large wilderness parks of the NCCN, including Mount Rainier National Park (MORA), North Cascades National Park Complex (NOCA), and Olympic National Park (OLYM). Across the three large parks, we documented the presence of 130 species and two hybrids, 96 of which were detected during point counts. For 57 species (all species for which we amassed at least 84 point count detections over the period 2005–2020), we present the total number of detections of each species on each park’s annual panel transects during the 2005–2020 field seasons. We caution, however, that these detection totals have not been adjusted for differences in survey effort, observer effects, or potential differences in detectability of birds between years; such adjustments will be made in conjunction with trend analyses in a future multi-year report. In the summer of 2020, we were scheduled to survey the grid at SAJH. However, we decided to drop the surveys there because of the COVID-19-related safety risks of traveling to an island when there were still stringent statewide rules about traveling during that phase of the pandemic. The number of bird detections on annual-panel transects across all three large parks decreased by 401 between 2019 and 2020, though the magnitude of the change in detections varied substantially among the parks. At NOCA there was an increase of 225 detections on annual-panel transects, though when factoring in the increase in point counts conducted in 2020, the average number of birds per count actually decreased slightly (5%) from 2019. At both MORA and OLYM, detections decreased between 2019 and 2020. When factoring in the number of point counts conducted each year, both parks saw a substantial decrease in the average number of birds per count (a decline of 24% at MORA and 19% at OLYM). Many species were nonetheless detected in slightly or moderately greater numbers in the three large parks in 2020 than in previous years. A few of these species include yellow-rumped warbler, Nashville warbler, black-throated gray warbler, warbling vireo, and song sparrow. Each of these species had more detections in 2020 than in any of the previous 14 years. Interpretation of these results will be completed as part of the next multi-year trend analysis, which will account for annual variation in survey effort, observer effects, and detection probability.
- Type
- Published Report
- Authors
- Holmgren, Amanda; Wilkerson, Robert; Siegel, Rodney; Ransom, Jason
- Date of Issue
- 2021-11
- Publisher
- National Park Service
- DOI
- 10.36967/nrr-2288211
- Units
- MORA , NOCA , NRSS , OLYM
- Keywords
- Abundance, alternating panel, American Camp, American robin, annual panel, annual report, Avian, Biology, Bird, black-throated gray warbler, dark-eyed junco, Density, Detectability, Distribution, English Camp, European starling, gray-crowned rosy-finch, hermit thrush, hermit warbler, house wren, landbird monitoring, marbled murrelet, Monitoring, Nashville warbler, Observation, Pacific wren, Pacific-slope flycatcher, pine siskin, Point Count, Presence, red-eyed vireo, song sparrow, Swainson’s thrush, Townsend’s warbler, Townsend’s/hermit warbler hybrid, Transect, Trend, varied thrush, warbling vireo, yellow-rumped warbler
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Birds , Ecological Framework: Biological Integrity | At-risk Biota | T&E Species and Communities