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2019-2021 Palila abundance estimates and trend

January 24, 2022

The palila (Loxioides bailleui) population on Mauna Kea Volcano, Hawai‘i Island, was estimated from annual surveys in 2019−2021, and a trend analysis was performed on survey data from 1998−2021. The 2019 population was estimated at 1,030−1,899 birds (point estimate: 1,432), the 2020 population was estimated at 964−1,700 birds (point estimate: 1,312), and the 2021 population was estimated at 452−940 birds (point estimate: 678). Since 1998, a visual inspection of the size of the area containing palila detections on the western slope based on the minimum/maximum elevations has not shown a substantial change, indicating that the range of the species has remained stable; although this area represents only about 5% of its historical extent. During 1998−2005, palila numbers fluctuated between 4,000 and 6,000, followed by a steep decline. After 2010, palila estimates stabilized around an abundance of 2,000 with a much slower rate of decline. The decline during 1998−2021 was on average 229 birds per year with very strong statistical support for an overall downward trend in abundance. Over the 23-year monitoring period, the estimated rate of change equated to an 89% decline in the population.

Publication Year 2022
Title 2019-2021 Palila abundance estimates and trend
Authors Ayesha Genz, Kevin W. Brinck, Chauncey K. Asing, Lainie Berry, Richard J. Camp, Paul C. Banko
Publication Type Report
Publication Subtype State or Local Government Series
Series Title Hawaii Cooperative Studies Unit Technical Report
Series Number 101
Index ID 70227797
Record Source USGS Publications Warehouse
USGS Organization Pacific Island Ecosystems Research Center