The State of Winter Wrens
The numbers of Winter Wrens counted during Mountain Birdwatch surveys have been declining since at least 2012. Since 2011, the overall numbers of Winter Wren in our study area have changed by -3.41% per year (95% Bayesian credible interval = -4.19% to -2.62%). This equates to a 24% overall reduction (95% Bayesian credible interval = 19% to 29%). Interestingly, Winter Wren declines have a longitudinal and latitudinal pattern–the declines become less severe as one moves from Maine towards the Catskills of New York. These declines are supported by the North American Breeding Bird Survey results from the last decade within the Atlantic Northern Forest Bird Conservation Region. In both data sets, Winter Wren numbers fluctuate up and down frequently. These fluctuations may be related to severe winter mortality.Mean annual population trends (below) for Winter Wren from 2011 through 2019. A red dot indicates strong evidence for a negative trend. An orange dot indicates a likely negative trend. A trend of -2%, for example, indicates that the number of Winter Wrens in our study area has declined by an average of 2% each year from 2011 through 2019.
|Region||Mean annual trend (%)||95% credible interval|
|All regions combined||-3.41||(-4.19, -2.62)|
|New York (state)||-2.89||(-4.08, -1.70)|
|New York (Catskills)||-1.65||(-3.09, 0.00)|
|New York (Adirondacks)||-3.20||(-4.60, -1.80)|
|New Hampshire||-3.85||(-5.04, -2.71)|
Globally: Probably stable
Data collected by the Breeding Bird Survey indicate that Winter Wren numbers across much or Canada and the U.S. are higher than they were in the 1970s. Since 2000, however, many populations of Winter Wrens appear to have declined.
Opportunities for Conservation
The long-term stability of Winter Wren populations suggests that the species is not in need of any immediate or specific conservation intervention. Most importantly, we can continue to provide complex, mature forests that offer safe nesting and wintering habitat. Because of the vulnerability of Winter Wren to harsh winter weather, we should continue monitoring populations, especially given the risk of increasingly volatile and severe winters due to human-caused climate change.