2017-2018 Palila abundance estimates and trend

The palila (Loxioides bailleui) population was surveyed annually from 1998–2018 on Mauna Kea Volcano
to determine abundance, population trend, and spatial distribution. In the latest surveys, the 2017
population was estimated at 1,177−1,813 birds (point estimate: 1,461) and the 2018 population was
estimated at 778−1,420 (point estimate: 1,051). Only two palila were detected outside the core survey
area during a mountain-wide survey in 2017, suggesting that most, if not all, palila inhabit the western
slope during the annual survey period. Since 1998, the size of the area containing palila detections on
the western slope did not show a significant change, suggesting that the range of the species has
remained stable; although this area represents only about 5% of its historical extent. During 1998−2003,
palila numbers fluctuated moderately (coefficient of variation [CV] = 0.20). After peaking in 2003,
population estimates declined steadily through 2011; since 2010, estimates have continued to decline at
a slower rate. The average rate of decline during 1998−2018 was 168 birds per year with very strong
statistical support for an overall declining trend in abundance. Over the 21-year monitoring period, the
estimated rate of change equated to a 76% decline in the population.