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Loon Program - Wyoming
Loon Program - Wyoming

Loon Research in Wyoming

The Common Loon is listed by Wyoming Game & Fish as a Tier 1 Species of Greatest Conservation Need and is considered the rarest breeding bird in Wyoming. The population of only 21 territorial pairs can be found on lakes in the northwest portion of the state in Yellowstone National Park, Grand Teton National Park, and the Bridger-Teton and Caribou-Targhee National Forests. These loons are at the southern extent of the species' range and are isolated by over 200 miles from the nearest breeding population.

Lead Investigators: David Evers and Lucas Savoy
Contributing BRI Staff: Chris Persico, Kate Taylor, and Jeff Fair

Wyoming Status Report  for the Common Loon


Wyoming’s landscape is a study in contrasts, from shortgrass prairies and sagebrush steppes to the stunning peaks of the Rocky Mountains.

Yellowstone National Park is dedicated to preserving the state’s natural environments and native species. One such species, the Common Loon, is in danger of disappearing. Since the mid-2000s, this population has declined by nearly 42 percent and is considered one of the most southern populations in its range.

The Common Loon is considered the highest ranked Species of Greatest Need by the Wyoming Game and Fish Department.

Download Status Report.

Project Overview

Project Overview

In Wyoming, the Common Loon is the rarest breeding bird; they are listed as a Species of Greatest Conservation Need, as determined by the Wyoming Game and Fish Department. In 2012, Biodiversity Research Institute (BRI), in partnership with Yellowstone National Park (YNP), initiated a study to monitor and understand the local breeding loon population. In 2013, BRI created a dedicated working group in collaboration with governmental agencies including Yellowstone and Grand Teton National Parks, the Wyoming Game and Fish Department, and Bridger-Teton and Caribou-Targhee National Forests. The goals of BRI within the Wyoming Loon Working Group are to ensure that Wyoming’s small and isolated breeding population of Common Loons is self-sustaining. A wider understanding of loon ecology and threats will be important to assist governmental agencies with management and outreach efforts.


Current Status

With only 22 observed territorial pairs, the Wyoming loon population is one of the smallest and most isolated in the species range (Figure 1). This population is not only the most southern loon population in the west, but it is also isolated from contiguous populations to the north by more than 220 miles. This makes immigration, and therefore dispersal and rescue from other populations, unlikely. The breeding population is distributed across:

  • Yellowstone National Park—16 pairs;
  • Caribou-Targhee National Forest—5 pairs;
  • Bridger-Teton National Forest—1 pair; and
  • irregularly in Grand Teton National Park.

Surveys from 2015-2019 identified several lakes with oversummering individuals and occasionally territorial pairs in the Wind River Range.

Despite the small size of the population, the number of territorial pairs in Wyoming has been trending upward since BRI began conducting standardized surveys in 2013 (when only 14 pairs were observed).

Loon productivity is best measured as chicks surviving (i.e., those living at least 6 weeks) per territorial pair. In Wyoming, 20 of the 30 years of measured productivity since 1989 were above the well-established sustainability threshold of 0.48 CS/TP value. This statistic is encouraging. For the past nine years, productivity has been above 0.48 CS/TP, which may be related to the increase in territorial pairs now being observed. Having exceptionally low productivity years, such as in 1993, 2004, 2008, and 2011, are typical of loon populations over time. Conversely, exceptional years were recorded in 1989, 2014, and in 2019.

Conservation Concerns

Conservation Concerns

Loons are long-lived; they have relatively low annual productivity and a poor ability to colonize new breeding areas. Given its small size and disjunct location, the breeding loon population in Wyoming is at particularly high risk of local extinction and is highly susceptible to coastal threats (for first summering and wintering individuals). During the breeding season, general threats to this population include: (1) direct human disturbance to nests and chicks and take of adults; (2) water level fluctuations (especially related to climate change); (3) changes in prey abundance and composition; and, (4) contaminants (e.g., lead and mercury) and toxins (e.g., cyanobacteria). On the wintering grounds, Wyoming’s loon population is susceptible to hazards such as marine oil spills and commercial fishing nets.

Recommendations for 2020

Evidence of the loon’s ability to acclimate to changing conditions demonstrates that properly designed conservation efforts can often be beneficial. General threats to North America’s loon population are well-established (Figure 6). In Wyoming, BRI’s research over the past seven years recommends prioritizing the following actions to help understand and protect loon breeding populations and maintain their long-term sustainability.


  • Continue to conduct standardized surveys of the breeding population, including the Wind River Range.
  • Continue to track color-banded adults and returning juveniles to determine site fidelity, local territory movements, age at first breeding, and individual performance.


  • Continue the capture, banding, and sampling of loons to track individuals and determine health including contaminant body burdens (e.g., mercury and lead and stable isotopes).
  • Determine inter- and intraseasonal movements through the use of geolocators and satellite transmitters.


  • Expand the use of artificial nest platforms to mitigate loss of productivity due to water level fluctuations. Use avian guards.
  • Continue closures of nest sites vulnerable to human disturbance, using ropes and floating signs, and/or restrict activities on small lakes during the nesting period.
  • Continue working with YNP biologists to modify gillnetting locations and timing to reduce loon bycatch.


  • Continue to create a greater awareness of the presence and requirements of breeding loons using dioramas, exhibits, communication pieces, and video and slide presentations.
  • Add signs, posters, or other educational materials at boat launches, trailheads, kiosks, and visitor centers.

Project Funding

The National Park Service provided initial funding for this project in 2012 and 2013. Additional funding came from the Wyoming Governor’s Big Game License Coalition in 2013. The Ricketts Conservation Foundation generously provided funding from 2013-2018.
2020 WGFD Research and Monitoring Summary


BRI, in collaboration with Ricketts Conservation Foundation, Wyoming Game & Fish Department (WGFD), Yellowstone National Park, recently published a two page summary brochure titled "Common Loon Research and Monitoring in Wyoming." 

Click here to download the WGFD summary report.

Photo Credits: Header photo © BRI-Jonathan Fiely; Common Loons © Daniel Poleschook
Biodiversity Research Institute