A threatened species manages to survive on Stratton MountainBy Louise Jones
Photography by Hubert Schriebl
A rare bird is causing a lot of excitement on top of Stratton Mountain. The Bicknell's thrush is medium-sized, with a spotted breast, olive-brown or brown back, purplish legs and a yellow or yellow-orange lower jaw; the males and females look alike. They have an average life span of five years, but biologists at the Vermont Institute of Natural Science have found the two oldest Bicknell's on record at their Stratton research station-a nine year-old female in 2005 and a ten year-old male this past summer. The birds nest in summer on the tops of the higher mountain peaks of northern New England, New York and southern Canada, and are among the least-known breeding birds in North America, rarely seen in migration. Chris Rimmer, director of the Conservation Biology Department at VINS, says that there are "in the ballpark of 25-40,000 Bicknell's thrushes although we have to stress that there is little precision around that figure. Our habitat projections indicate that Vermont has about eight percent of the total Bicknell's thrush habitat in the United States. Thus, we could estimate that 2000-3200 thrushes inhabit Vermont." To compare, I asked him how many robins in Vermont. "A wild guess would be at least one hundred times as many robins and maybe even five hundred times as many," he said. According to Kent McFarland, a conservation biologist with VINS, "This is the only endemic song bird species in the northern Appalachians. There are other birds that use the same habitat-black-polled warblers, magnolia warblers, cross bills and pine siskins-but the Bicknells' thrush is the only one that has to be there. It's their only habitat."
The Bicknell's Thrush Project studies the demographics and habitat of the bird, covering the whole northern Appalachian range, and is funded by government and private grants and donations. When the project began, the first job was to investigate every mountaintop in the northeast to see if the bird existed there at all. In Vermont, wildlife biologists started the work in 1992 near Mt. Mansfield; they have been at Stratton since 1997.
It's intensive work. On Stratton Mountain the study is centered at two areas, or plots, one at the ski area and one near the fire tower. Each summer the staff nets the birds and examines them. Before releasing them, the biologists attach a colored band to each netted bird's leg with what McFarland calls an "avian social security number," used for tracking and identification...
