Ecology and Vulnerability

Blue-winged Teal

Background
Massachusetts is at the eastern edge of the blue-winged teal's distribution. The historical status of blue-winged teal in Massachusetts is unclear, but the current breeding population is relatively small and dispersed¹.  The species is, however, common during spring and fall migrations between wintering and breeding grounds².  Blue-winged teal breed from coast to coast, but their distributional center is in the Prairie Pothole Region of the Northern Great Plains.  This is an area characterized by a high density of shallow wetlands that produces 50-80% of the continent’s ducks³.  The blue-winged teal appears to be more sensitive to cold than most duck species and winters from the Gulf coast south through Mexico, the Carribean, Central America, and South America^1,4.

Climate Impacts
Because the Prairie Pothole Region produces a large proportion of the continent’s ducks, events in this region can greatly impact entire populations.  Duck production has been shown to vary greatly from year to year due to changes in the amount of wetlands in this region linked to variable weather patterns⁵.  Climate models project increased drought conditions for the region, resulting in northward shifts in the ducks' breeding distribution, with the potential for dramatic reductions in overall duck populations³.  In addition, loss of pothole wetlands through drying can concentrate predators, which would have a greater impact on nesting ducks in the remaining pothole wetlands.  Dramatically reduced duck populations in the Prairie Pothole Region could also potentially reduce the number of blue-winged teal that migrate through the state of Massachusetts.

Climate change also has the potential to impact the small local breeding population of blue-winged teal in many ways.  Climate models generally predict increased short term drought conditions, reduced summer stream flows, and increased duration of low summer flows in the northeastern US⁶.  Typical responses to drought conditions in ducks include less breeding, decreased clutch sizes (number of eggs laid by nesting pair), shortened breeding season, decreased frequency of renesting, and other responses that reduce reproduction^3,7,8,9.  Changes in migration timing are likely, and have already been documented for blue-winged teal in Massachusetts and New York¹⁰.  Modeling by the US Forest Service predicts the loss of breeding populations from the state of Massachusetts, along with a range-wide decrease in both distribution and abundance¹¹.