Cooperative Fish and Wildlife Research Units Program: Massachusetts
Education, Research and Technical Assistance for Managing Our Natural Resources

Wilson, T.L., E.A. Weiss, T. Shepherd, L.M. Phillips, and B. Mangipane. 2017. Monitoring bald eagles in Southwest Alaska Network parks: Protocol narrative. Natural Resource Report NPS/SWAN/NRR—2017/1382. National Park Service, Fort Collins, Colorado.


This protocol outlines the methods for collecting, managing and reporting monitoring data for bald eagles in the Southwest Alaska Network (SWAN), as described in the SWAN Monitoring Plan (Bennet et al. 2006). The study design, data collection methods, and analytical protocols have been previously published in the Journal of Wildlife Management (Wilson et al. 2014) and in two National Park Service Natural Resource Technical Report (NRTR) series publications (Thompson et al. 2009, Thompson and Phillips 2011). The methods described here also closely follow those outlined in the United States Fish and Wildlife Service’s post-delisting monitoring plan (USFWS 2009).

As apex predators, bald eagles are expected to be sensitive to changes in the food web that can affect population dynamics and productivity. As a result, bald eagle reproductive performance can be an important indicator of current and long-term changes in terrestrial, freshwater and marine systems (Thompson et al. 2009). To measure changes in bald eagle breeding populations, the following objectives will be addressed at sampling locations in the three largest park units in the SWAN: Lake Clark National Park and Preserve (LACL), Katmai National Park and Preserve (KATM), and Kenai Fjords National Park (KEFJ).

1) Estimate long-term trends in the abundance of bald eagle nests

2) Estimate long-term trends in the annual proportion of nests in which eagles attempt to reproduce (nest initiation)

3) Estimate long-term trends in annual nest productivity, defined as the mean number of chicks produced per initiated nest

A dual-frame sampling approach that combines two techniques (list and area frame) will be used to estimate abundance within a defined area of interest in each park (Haines and Pollock 1998; U.S. Fish and Wildlife Service 2009), as well as estimation of the dynamic properties of nest initiation status and productivity (e.g. nest survival, colonization, and extinction). This protocol and the SOPs in the accompanying document outline aerial survey methods used in the SWAN.