Land Trust and Electric Cooperative Team Up to Prevent Swan Mortality

While most birds disappear as winter’s cold hand grips Teton Basin and the lower Henry’s Fork, one notable exception arrives to spend the winter- the Trumpeter Swan.  Winter can be harsh in the service area of Fall River Rural Electric Cooperative, and the cooperative is working with the Teton Regional Land Trust to ensure Trumpeter Swans who spend the winter here don’t face additional threats from power lines.

The Teton Regional Land Trust and Fall River are coordinating a project to add and/or replace at least 120 bird diverters on power lines in areas frequented by wintering Trumpeter Swans.  Bird diverters hang from power lines, making them more visible to birds in flight.

“Fall River selectively installs bird diverters on lines that cross rivers and other areas that are frequented by large birds,” says Larry Hamilton, Manager of Operations.  Hamilton notes that the cooperative sometimes receives objections from local landowners who don’t like how the diverters look, but the number of bird deaths and outages the diverters prevent makes it worthwhile.

Although bird diverters have been installed on several lines throughout the Fall River service area, older models of diverters have a tendency to break off during high winds.  New bird diverters are built to withstand the gale-force winds often seen during the winter in our area.  Although several studies on the effectiveness of bird diverters are yet to be completed, anecdotal evidence shows they do prevent bird mortality.

The Rocky Mountain Population (RMP) of Trumpeter Swans is an Idaho Species of Greatest Conservation Need, although the population has greatly rebounded since the early part of the last century.  By 1930, commercial harvesting had reduced the once abundant Trumpeter Swan to near extinction throughout its range south of Canada.  Only about 70 swans survived in the Greater Yellowstone region of Idaho, Montana and Wyoming by 1932.

Trumpeter swan restoration and management programs that began in the mid-1900s in the U. S. and Canada gradually boosted trumpeter swan populations, but the RMP Trumpeter Swans still face threats from lack of winter range and habitat alteration.

Teton Valley and the lower Henry’s Fork, including the Texas Slough area, are key wintering areas for the 5,000 RMP Trumpeter Swans.  A mid-winter count of waterfowl last year by the U.S. Fish and Wildlife Service revealed that nearly 70% of RMP Trumpeter Swans were spending their winter in Eastern Idaho. ■