Kittlitz’s murrelet monitoring in Glacier Bay National Park and Preserve 2010–2018: Synthesis and program review

Hoekman, Steven

The Kittlitz’s murrelet (Brachyramphus brevirostris, hereafter “KIMU”) is a small, rare seabird endemic to Alaska and northeastern Russia (Day et al. 1999). Because of their role as integrators of marine and terrestrial ecosystems and intrinsic conservation concern, breeding season populations of KIMU and co-occurring marbled murrelets (B. marmoratus, “MAMU”) in Glacier Bay National Park and Preserve were selected for the Southeast Alaska Inventory & Monitoring Network (SEAN) Vital Signs Monitoring Program (Moynahan et al. 2008). Building on prior surveys for these species (Lindell 2005, Drew et al. 2008, Kirchhoff 2008, Kirchhoff et al. 2010, Kirchhoff and Lindell 2011) in Glacier Bay (“GLBA”), the SEAN implemented a long-term monitoring protocol (the “Protocol”, Hoekman et al. 2013a) with objectives (primarily for KIMU, secondarily for MAMU) of annual estimation of on-water abundance and spatial distribution for populations and of high power to detect 33% population decline over 15 years. After pilot surveys in 2009, boat-based line transect surveys (Buckland et al. 2001) consisting of an augmented, serially alternating panel design, with permanent transects sampled annually and panels sampled every third year, have been conducted using Protocol methods during early July 2010-2018. The Protocol stipulated periodic assessment to assure monitoring performance and inform potential enhancements. My intent here was to: • Summarize results of Protocol monitoring and related research activity. • Interpret Protocol results in context of current scientific literature. • Assess monitoring performance, key assumptions, and capacity to meet Protocol objectives. • Provide recommendations for management of murrelets in GLBA and for potential enhancements to the Protocol. This report is not intended to provide definitive estimates of species-specific density and abundance or estimates of trend in population abundance. Instead, I summarized results presented in annual monitoring reports pertaining to: species-specific abundance, spatial distributions of populations, estimation of detection probability, and conditions during annual surveys. I interpreted monitoring results in context of results from other surveys for these species, relevant scientific literature, and my assessment of Protocol performance. Key assumptions of Protocol methods were tested using analyses of Protocol data and additional field experiments. Incomplete detection of murrelets compelled estimation of detection probability via line transect methods, which required assumptions about estimated detection functions and accuracy of distances estimated by survey observers (Buckland et al. 2001). Additional to evaluating robustness of estimated detection functions, I analyzed distance calibration assessment data collected during Protocol operations to assess performance of survey observers in distance estimation.

Kittlitz’s murrelet monitoring in Glacier Bay National Park and Preserve 2010–2018: Synthesis and program review

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