LAKEVIEW – With a roar, the huge propellers mounted on the back of the airboat come to life.
A gentle push of the throttle and Red Rock Lakes Refuge assistant manager Tom Reed sends the boat and its passengers across the mirror-like waters of upper Red Rock Lake.
All eyes sweep the horizon, searching for telltale white dots on the placid waters.
Dave Olson, the refuge’s wildlife biologist points left and Reed swings the boat toward a pair of trumpeter swans frantically heading for the far-off shoreline.
The swans are molting and can’t fly.
It doesn’t take long before Olson pulls one of the big birds into the boat.
Armed with a tiny transmitter, the researchers hope to use space-age technology to unlock secrets of the trumpeter swans that live in the Centennial Valley during the summer.
The valley is located in extreme southwestern Montana, and parallels the Idaho border.
On board today is Tom Maechtle, a consultant with Bighorn Environmental Consulting of Sheridan, Wyo. One of the pioneers of using satellite telemetry to track birds along migration routes, Maechtle is here to show Reed and Olson the technique of mounting a small transmitter on the back of a bird.
Maechtle has used similar transmitters since 1992 to track peregrine falcons along their migration routes from the Arctic Circle to the Gulf Coast and beyond.
He’s mounted transmitters equipped with altimeters on turkey vultures.
And he’s seen the technology get better and the transmitters grow smaller and more powerful.
In this case, the swan will be packing this transmitter along during its travels for the next two years.
In an effort to preserve the tiny batteries that power the unit, it will turn on and off at set intervals.
“We want to find out the route they take and where they end up in the winter,” said Reed as he holds the bird steady for a few final adjustments. “Everyone is concerned about the habitat they’re using and where their migration routes are.”
No one is quite sure where all the trumpeter swans that summer in the Centennial Valley spend the winter months.
Fewer than 10 years ago, those birds stayed in the valley and were dependent on a feeding program that had been around since 1935.
During the winter of 1992-93, the winter handouts ended after officials began to worry about an influx of swans from Canada and the potential for disease transmission among the birds crowded on the pond where the feeding occurred.
The hope was the birds would develop their own migration patterns.
“We’re hoping this will begin to help us start to understand what the birds are doing,” Reed said. “We know the six birds that will be fitted with transmitters isn’t enough to let us know exactly what’s occurring, but it is a start.”
A management plan revised in 1998 for the Rocky Mountain population of trumpeter swans recognized that winter distribution is the foremost problem for the birds that live in Montana, Idaho and Utah.
It recognized the significance of the flock that breeds within the Centennial Valley and wanted to institute efforts that would lead toward the birds migrating to more suitable winter habitat.
“To do that, we need to know where the birds go in the first place,” Reed said. While the satellite telemetry operation is expensive – it costs about $2,000 per bird, plus satellite access fees – Reed said there really isn’t any other way to get this kind of information.
The information obtained by winter surveys can be sketchy and affected by bad weather.
Reed said the project will help determine migration routes as well as winter and pre-breeding habitats for a portion of the Centennial Valley population.
“It is crucial for managers to have this information in order to make decisions that will continue winter range expansion and improve production in the Centennial Valley and Rocky Mountain populations,” he said.
Swans, like all waterfowl, appear to need good nutrition to be successful in reproduction, Reed said.
Poor pre-breeding conditions in female waterfowl has been linked to failure to breed, delayed nest initiation, reduced clutch size, and decreased nest attentiveness during incubation, he said.
Swans consume an estimated 20 to 30 pounds of vegetation a day during the summer months in the Centennial Valley, Reed said.
A recent summer count turned up between 70 and 80 swans on the refuge.
“That’s really not all that great and we’re not really sure why,” he said. “There’s still so much more we have to learn about these birds.”
Published on Thursday, August 02, 2001. Last modified on 8/1/2001 at 11:38 pm
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