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Loon Program - Montana
Loon Program - Montana

Loon Research in Montana

Montana has the largest population of Common Loons in the western United States with 72 territorial pairs. While the number of territorial pairs has fluctuated since 2006, the overall number of pairs has increased. In order to support the expanding work conducted by Montana Fish, Wildlife, and Parks and the Montana Common Loon Working Group, BRI staff will broaden current monitoring efforts to improve our understanding of Montana loon population dynamics to ensure the continued growth of the population.

Lead Investigator: Allison Byrd

Study Goals

Study Goals

Assist MFWP with surveys of loon territories and with identifying research in support of the Montana Comprehensive Fish and Wildlife Conservation Strategy Plan, including:

  1. Working to develop new research projects and to maintain current projects to best guide conservation and management. Such projects include documenting adult and subadult site fidelity, tracking intra- and inter-seasonal movements for adults and sub-adults, and investigating risks from contaminants in breeding, staging, and wintering areas.
  2. Expanding current monitoring efforts and strategies beyond traditional study lakes through collaboration and coordination with all members of the Montana Common Loon Working Group. Data obtained through monitoring will be used to (a) identify and maintain the current number and spatial distribution of nesting territories, and (b) identify and protect potential territories with suitable habitat quality.
  3. Compiling and analyzing existing loon datasets (e.g., site fidelity, local movements, and reproductive success).

Study Region

The current study area is the northwest corner of Montana.
The current study area is the northwest corner of Montana.
Methods of Gathering Data

Methods of Gathering Data

Lakes will be observed using binoculars or a spotting scope to determine the presence or absence of loons. Kayaks or boats will be used to survey lakes when appropriate. If use of watercraft is not possible, lake perimeters where breeding is occurring or suspected will be searched on foot for the presence of nests.

Capture and Banding
Loons will be captured using both nocturnal and diurnal techniques developed by BRI. Captured loons will be banded for individual identification using unique combinations of color-marked bands and numbered U.S. Geological Survey aluminum bands.

Blood and Feather Collection
We will follow established tissue sample collection protocols. We will non-lethally collect loon blood samples to evaluate short-term mercury accumulation in the loons. Feather samples will be collected from the adults (and from juvenile loons with fully emerged feathers) to provide an indication of long-term mercury accumulation.

Egg Collection
Loon eggs will be collected when a nest is confirmed abandoned or has been over-incubated (due to inviable egg/s). The average length of incubation for Common Loons is 28 days; therefore eggs will not be deemed inviable until they have been incubated many days or weeks beyond this length of time.

Carcass Collection
Biologists may encounter deceased loon adults or chicks. If this occurs, the carcass will be collected in a sealable plastic bag and marked with the location of the carcass, the date, and any other pertinent information. When possible, a GPS location of the carcass will be taken. If the carcass is reasonably fresh, it will be refrigerated. Michelle Kneeland, DVM will be contacted to determine if she is available for a necropsy. If Dr. Kneeland is not available, or if the carcass is decaying, it will be stored in a freezer until a necropsy can be performed.

Expected Deliverables/Outcomes

Expected Deliverables/Outcomes

1. Conduct surveys via shoreline, kayak, boat, and plane

  • Assist survey efforts and document unpaired adults
  • Assist in surveying lakes within MFWP study areas
  • Track intra- and inter-seasonal movements of color-marked adults and sub-adults
  • Assist MFWP biologist with coordination of return rates of loons and analyzing site fidelity

2. Assist MFWP with banding efforts

  • Coordinate deployment of geolocators when necessary
  • Assist with/coordinate diurnal capture
  • Assist with nocturnal capture as needed

3. Coordinate loon egg and carcass collection

4. Set-up, monitor, and remove nest cameras when appropriate; disseminate photos, video, and information

5. Assist MFWP biologist with:

  • Data management and analysis
  • Manuscripts when appropriate
  • Study design
  • Additional loon-related projects as needed

6. Monitor lakes in Glacier National Park where gill-netting activities are occurring

7. Assist the Wyoming and British Columbia loon projects when necessary for capture or surveys

8. Implement/Initiate further research projects when relevant



State biologists, nongovernment agencies, national park biologists, tribal lands biologists, university scientists, as well as interested citizens and lakeshore homeowners, all work collaboratively to study and protect Montana’s Common Loon population.
  • Montana Common Loon Working Group
  • Montana Fish, Wildlife & Parks 
  • Montana Loon Society
  • Montana Department of Natural Resources and Conservation
  • U.S. Forest Service Glacier National Park
  • Plum Creek Timber Company
  • Avista Corporation
  • Confederated Salish and Kootenai Tribes
  • Private Citizens
  • U.S. Fish & Wildlife Service
  • University of Montana
Montana Status Report for the Common Loon


Montana’s topography is defined by the Continental Divide, which creates distinct eastern and western regions that encompass snow-covered mountains, prairie lands, and alpine forests. Glacier National Park is dedicated to preserving the state’s natural environments and native species. One such species, the Common Loon, is increasing after years of dedicated conservation and management. Although the number of territorial pairs has increased by 23 percent since 2000, continued health requires diligent monitoring.

Download Status Report.

Photo Credits: Header photo: © BRI-Allison Byrd; Scope on lake © BRI-Allison Byrd; Loon © BRI-Allison Byrd; Kayaking MT lake © BRI-Allison Byrd
Biodiversity Research Institute