City of Seattle, Seattle Public Utilities, Marbled Murrelet Habitat Enhancement Experiment 2010, Cedar River Municipal Watershed, King County, WA

This experimental project aims to enhance nesting habitat for the marbled murrelet through active habitat restoration in second-growth forests. The project was conducted within the Cedar River Municipal Watershed (CRMW) in Washington State, with the goal of determining if silvicultural treatments, such as creating canopy gaps and tree topping, can accelerate the growth of tree branches suitable for murrelet nesting.

The project was implemented in 2010 at a 75-acre site within CRMW. Treatments included removing surrounding trees to increase canopy openness ("gaps"), topping trees to stimulate branch growth, and combining both methods. The site was specifically chosen for its proximity to the murrelet detections in nearby old growth stands, and site suitability in terms of tree age, species composition, and manageable topography.

Data collected focused on tree growth and structure characteristics critical to murrelet nesting. A total of 48 trees received treatments, which were systematically compared to untreated controls to assess outcomes. The initial implementation confirmed logistical feasibility and budget adherence, with plans for monitoring and resampling established for the 2020s.

If successful, these techniques could be replicated across various environmental conditions to expand viable nesting habitat for the marbled murrelet, directly supporting conservation objectives outlined in the CRMW Habitat Conservation Plan.