Current bird species distributions are correlated with climate. Fossil record reveals that past periods of climatic instability have produced dramatic shifts in species’ geographic ranges.
Adaptation to climate change is less likely when climate change occurs rapidly.
The current rate of climate change is unusually rapid. Short-term responses may include shifts in distribution and changes in the timing of migration and breeding.
Phenological shifts in prey bases have been shown to affect bird populations: failure to adapt to a change in the timing of insect emergence has been cited as a cause of population collapse among some European bird species.
Some predicted seasonal changes in Vermont that may affect breeding birds include: warmer winters, more overwintering of insects, multiple melt events in the winter, earlier arrival of spring, earlier bloom dates of many plant species, earlier last spring frost, earlier ice-out of lakes and ponds, hotter summers, more heavy rain events, greater frequency of 1-2 month droughts, increased warm-weather insects, and warmer fall temperatures.
Changing distributions are likely to be observed within the next 25 years.
- Montane forests of spruce and fir are apt to be most sensitive to the changing climate.
- Not all birds will be adversely affected. Under one scenario, 38 percent of bird species in Vermont were predicted to occupy smaller ranges in the future, whereas 44 percent were predicted to expand their range. (see reference)
- Some of Vermont’s iconic species such as Common Loon and Hermit Thrush, and several Neotropical migrants like Wood Thrush, Veery, and Bobolink, are projected to decline significantly under all climate-change scenarios
- Species that have expanded into Vermont from the south (e.g., Tufted Titmouse, Northern Cardinal) and species compatible with suburban habitats (e.g., Canada Goose) are expected to benefit.
Webinar: Regional Impacts of Climate Change on Forests and Bird Communities