Trumpeter Swan Production and Habitat in The Centennial Valley, Montana

The Trumpeter Swan Society (TTSS) initiated a pilot project in 2011 in the Centennial Valley to document existing conditions on historic trumpeter swan nesting territories. Swan production in the Greater Yellowstone region surrounding Yellowstone National Park has declined significantly over the past fifty years, particularly in the Centennial Valley, Montana, which historically has been the primary production area in Greater Yellowstone. Current low production raises serious concerns over the viability and sustainability of trumpeter swans in the Centennial and the entire region. The lack of a long-term comprehensive restoration strategy for Greater Yellowstone nesting swans, and particularly the changing management emphasis on Red Rock Lakes NWR, further emphasize the need to improve swan production in the Centennial Valley. Apparently suitable nesting territories are available and may be occupied but production is not occurring, and a growing number of non-breeding adult swans 74 are present. Lima Reservoir is the dominant water feature in the lower half of the Valley but widely fluctuating water levels affect quality waterfowl habitat, including some swan nesting territories and areas used intermittently by up to 150 non-breeding trumpeter swans. In cooperation with the Centennial Valley Association which represents 30 landowners in the Valley, TTSS monitored swan production and collected basic wetland information on the 15 most frequently used trumpeter swan territories outside Red Rock Lakes NWR. In some years, these territories have surpassed refuge swan production. This effort documented swan use and characteristics of nesting territories including wetland type and water availability, availability and quality of emergent and aquatic vegetation, and human influences such as livestock grazing, presence of fences in the wetland, and potential disturbances. Potential wetland enhancement projects were identified that could encourage trumpeter swan use. Trumpeter swan monitoring and site-specific habitat assessments are planned for the next 3-5 years.