To establish baseline, preconstruction data for evaluation of the possible effects of wind turbine construction on montane forest bird populations on East Mountain in East Haven, Vermont, we conducted field studies in June and July of 2004. Focusing on Bicknell's Thrush (Catharus bicknelli), our primary research objectives were to: (1) estimate population size and density; (2) estimate demography and survivorship by sex and age class; (3) document reproductive success; and (4) spatially analyze adult thrush home range size, movement patterns and behavioral ecology. Our censusing and nest monitoring encompassed all avian species, while our mist-netting and banding targeted Bicknell's Thrush, Swainson's Thrush (Catharus ustulatus), Yellow-rumped Warbler (Dendroica coronata), and Blackpoll Warbler (Dendroica striata). Overall, we mist-netted and banded 198 individuals of the four target species, a capture rate of 8.9 new birds/100 net hours. We banded 10 male and 8 female Bicknell's Thrushes. We monitored 3 radio-tagged female Bicknell's Thrushes for the duration of the study period and calculated widely varying home ranges of 2.3 - 11.3 ha for each. Four of 7 radio-tagged females were depredated, probably by short-tailed weasels, within 1-5 days of release. We monitored a total of 12 active nests of 5 species; of 11 nests whose outcomes were known, 8 (73%) were successful. Our sample included 4 nests of 3 female Bicknell's Thrushes; 2 of these nests fledged young. We detected a total of 135 individuals of 16 avian species on two census dates, for a mean of 9.6 birds per point count. The suite of species was very similar to that found on other Vermont peaks, with the exception of 3 species typically restricted to lowland spruce-fir forests in the Northeast Kingdom: Black-backed Woodpecker (Piciodes arcticus), Gray Jay (Perisoreus canadensis), and Boreal Chickadee (Poecile hudsonica). We estimate that as many as 18-20 individual male Bicknell's Thrushes and 10-12 females may inhabit the full extent of suitable montane fir-spruce habitat on East Mountain. Our 2004 field work, while limited in scope and duration, provides a solid foundation for future research and monitoring.
Ecology and Demography of Bicknell's Thrush on East Mountain, East Haven, Vermont: Evaluating Potential Impacts of Wind Turbine Construction
Title: Ecology and Demography of Bicknell's Thrush on East Mountain, East Haven, Vermont: Evaluating Potential Impacts of Wind Turbine Construction
December 01, 2004
Rimmer, C.; Faccio, S. (2004). Ecology and Demography of Bicknell's Thrush on East Mountain, East Haven, Vermont: Evaluating Potential Impacts of Wind Turbine Construction. Report by Vermont Institute of Natural Science. pp 25.