This article byon the valleys Trumpeter Swans, appeared in the JH news & Guide.
Half a century after they were nearly wiped out, trumpeter swans are holding steady in the Jackson Hole area.
But drought, climate change and diminishing natural wetlands pose real threats, wildlife managers such as Wyoming Game and Fish Department nongame biologist Susan Patla believe.
“The Jackson area has a stable population,” Patla said, “but it’s really something we ought to be paying attention to because the nesting swans in adjacent states in the same area have really shown declines.
“I think it’s time to really do some wetland work for swans in the Jackson area,” she said. “What we’re finding — because of climate change and drought — is that natural wetlands are drying up.”
Patla and others pay close attention to the ebb and flow of the population, counting the large white waterfowl from the air four times a year.
Because nine in 10 of the swans now present in the valley are seasonal migrants from Canada, winter is a deceptive time of year. But as informed birders know, the resident population of one of Wyoming’s largest and rarest nesting bird species is still relatively small and fragile.
Yellowstone National Park has lost almost all its breeding birds over the last three decades, Patla said, and eastern Idaho’s resident swans have seen “quite a decline.”
Conversely, Wyoming’s trumpeters are on the rise statewide. Resident adult swans have risen from an average of about 100 birds around 2006 to 180 adults last year, Patla said. The growth is attributed to introductions into new regions and habitat improvement projects in areas such as Star Valley and the Upper Green River.
“They’re doing great down there,” Patla said of the Upper Green. “They’ve doubled our state population and doubled our productivity, because of the success of the birds. That population is still growing strongly — and we haven’t seen the limits there.”
In parts of the Greater Yellowstone Ecosystem where trumpeter swan numbers are slumping Patla points to two causes: drought-caused habitat loss and disruption from increased human recreation.
The region’s trumpeters, known as the “tri-state” area population, spans Yellowstone park, southern Montana, Idaho’s Island Park and Teton Valley areas, Jackson Hole and south to Star Valley and the Upper Green. The regional population usually totals 400 to 500 adult swans, Game and Fish monitoring reports show.
Other trumpeter swan populations exist in Alaska, Canada, along the Pacific coast and in the Great Lakes area.
Trumpeter swans are one of the rarest and the largest nesting waterfowl species in Wyoming, and males can tip the scales at over 30 pounds. They eat almost exclusively aquatic vegetation and as a result depend on open water in the winter.
Come springtime in Jackson Hole the area’s swans have sometimes almost eaten themselves out of a home. March and April, Patla said, are a “pinch period” when many swans have been severely weakened by a lack of forage.
“I’ve picked up live swans that were so weak that a mink had started to eat its thigh,” she said.
As drought has diminished Jackson Hole’s natural wetlands, man-made ponds have emerged as some of the most important trumpeter swan habitat around the valley, Patla said.
“A lot of the swans now are most productive on managed wetlands, where we can control the water level,” she said. “You need a fluctuation to make a productive wetland.”
The South Park Wildlife Habitat Management Area is one example of a thriving wetland; last year resident swans there produced five cygnets, Patla said.
Four breeding pairs on natural National Elk Refuge ponds hatched a dozen young last year.
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