A follow-up from the Science Synthesis:
"In Washington, the marbled murrelet population declined by 4.6 percent annually from 2001 to 2013; a cumulative decline over 10 years of 37.6 percent. Populations had no detectable trends in Oregon and California."
Main Points From the Marbled Murrelet Chapter
- The assumptions of the Northwest Forest Plan (NWFP, or Plan) remain relevant for marbled murrelet conservation.
- Large late-successional reserves (LSRs) in moist coastal forests have successfully protected nesting habitat for the marbled murrelet in the short term. It would be important to evaluate any possible changes to the LSR system against the likelihood of adversely affecting murrelets.
- A long-term goal of the NWFP is to create more nesting habitat than existed on federal lands in 1994. Trends indicated that progress is being made toward this goal.
- Uncertainties remain around the effects of climate change on the murrelet's marine prey and nesting habitat. Future management and design of reserves will benefit from accounting for the anticipated effects of climate change.
- Murrelet populations remain at risk, but protections appear to have helped stabilize populations in some areas
- Based on population monitoring done at sea, the total murrelet population for the NWFP area is roughly 20,000 birds. This includes those nesting on federal as well as nonfederal lands. Population estimates are highly variable from year to year and have fairly wide 95% confidence intervals, averaging about ± 22 percent for estimates at the NWFP scale.
- Based on trend analyses summarized over the three states, murrelet populations may have been stable or nondeclining in Oregon and northern California since monitoring began in 2000, but have declined substantially in Washington from 2001 to 2015.
- Threats to population persistence includes loss of nesting habitat, poor recruitment of young owing primarily to nest depredation by jays and crows, and changes in prey abundance and quality in the marine environment. These changes in prey could be in response to climate change or other human-caused disturbances in the marine environment.