Mountain Ecosystem Studies
"…only a freak ornithologist would think of leaving the trails [on Mt. Mansfield] for more than a few feet. The discouragingly dense tangles in which Bicknell's Thrushes dwell have kept their habits long wrapped in mystery” (George Wallace 1939).
High elevation conifer forests of the Northeast support a distinctive bird assemblage and are threatened by airborne pollutants and human-related development. VINS initiated ecological and demographic studies of Bicknell's Thrush and other montane forest birds in 1992 in order to assess the conservation status of this avian community. Related research has included studies of mating systems, mercury levels, and ski area and wind turbine impacts, population monitoring and ecology.
To learn more about the natural history of Bicknell's Thrush and other high elevation songbirds, visit the Bicknell's Canadian Wildlife Service Bicknell's Thrush web site. An outstanding collection of photos, video, sounds and more...
Projects
 Mountain Birdwatch is a long-term monitoring program for Bicknell's Thrush and other mountain-dwelling songbirds. From the Catskills to Mount Katahdin, trained volunteers conduct dawn surveys along foot trails that pass through the region's most awe-inspiring forests. Participants experience the thrill of alpine adventure and help guide the stewardship of vulnerable mountain habitat. Contact: info@vinsweb.org
Mercury and Montane Songbirds
One of the most significant discoveries we have made is the presence of mercury in non-aquatic songbirds. The data on Bicknell's Thrush provide the most comprehensive information to date on mercury in a strictly terrestrial, insect-eating songbird. The results from this new study show that songbirds in mountain forests are accumulating mercury.
Bicknell's Thrush Habitat and Climate Change
Read about our new map of Bicknell's Thrush breeding habitat in the Northeast.
View a map from our model of Bicknell's Thrush habitat.
Global warming is poised to substantially change the climate in the Northeast if heat-trapping emissions are not curtailed, and the extent and impacts of the change depend on the choices that governments, businesses and citizens make today. By the end of this century, for instance, summers in Vermont could resemble ones in Tennessee if emissions continue unabated. But if emissions are reduced, summers in Vermont could resemble those of West Virginia. So concludes the first study released in October by the Northeast Climate Impacts Assessment (NECIA), a collaboration between the Union of Concerned Scientists (UCS) and a team of independent scientists from universities across the Northeast and the nation, including VINS Conservation Biology Department scientists.
Visit Climate Choices for more information.
Read the Vermont press release on our CBD Blog.
Effects of Development
Read our latest reports:
Evaluating the use of Vermont ski areas by Bicknell's Thrush: applications for Whiteface Mountain, New York.
Ecology and demography of Bicknell's Thrush on East Mountain, East Haven, Vermont: evaluating potential impacts of wind turbie construction.
 Population Connectivity of Bicknell's Thrush
Population connectivity for migratory species describes the amount of mixing of individual populations between summer and winter areas as well as the stop-over and staging locations between them. This includes natal dispersal, which for migratory organisms results from two migratory movements – birth place to winter grounds and then back to first breeding site. An understanding of population connectivity for Nearctic-Neotropical migratory birds has implications for many aspects of biology, including ecology, evolution, conservation, and epidemiology.
Read the full scientific paper.
A Strange Mating System
The behavior in which multiple unrelated males feed dependent nestlings is common in only one other North American bird species, Smith's Longspur. In our study, 75% of broods were sired by multiple males and 78% of broods were fed by multiple males. Some males had parentage in multiple broods in the same year, but females did not. Twelve of 14 males (86%) sired offspring in the broods that they fed. Females typically provided about half of feeds for a brood, while males appeared to adjust feeding in response to the number of male co-feeders. Multiple male feeders may allocate parental effort to broods based on probability of paternity, to enhance mating access, as misdirected parental care, or via some combination of these factors. A harsh environment which exceeds the polyandry threshold, and a strongly male-biased sex ratio may also influence the number of feeders. Many aspects of this secretive bird's breeding ecology remain obscure, in particular the effects of food availability, female dispersion, female reproductive synchrony, mating access, and kinship.
Read the full scientific paper.
Long-term Demographics of Montane Songbirds
Avian Productivity, Red Squirrels and Balsam Fir Mast – We have discovered a biennial cycle involving balsam fir cone mast, red squirrels and possibly other small mammals, and bird demographics. From 1995-2001, we annually monitored balsam fir reproduction, bird densities and reproductive success, and red squirrel densities. High cone production occurred biennially in late summer and fall of even-numbered years and was followed by immigration and breeding by White-winged Crossbills, Pine Siskins and red squirrels. Open cup-nesting birds experienced extremely low rates of nest success in summers following heavy cone mast, probably due to nest depredation by red squirrels and other small mammals, and high success following mast failures. Analysis of demographic variables indicates that our study populations are sinks in odd years, sources in even years, and barely break-even overall.
Bicknell's Thrush on the Wintering Grounds
VINS began field studies to assess the distribution, habitat use, and conservation status of Bicknell's Thrush in the Dominican Republic in December of 1994. Ten years and nearly 20 visits later, VINS is spearheading collaborative, islandwide efforts to protect birds and their habitats. Our current work integrates field research and monitoring with local training, outreach, and capacity building.
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