A study by the National Audubon Society and the James C. Kennedy Waterfowl and Wetlands Conservation Center at Clemson University of 16 common winter duck species in the southeastern United States shows that populations have shifted north over the past 50 years due to changes in temperature and global warming .
The study, published in the Journal of Wildlife Management, is based on data collected during Audubon’s annual Christmas Bird Count (CBC) from 1969 to 2019. The CBC includes both amateur bird watchers and scientists who report on local bird populations each December and January.
“We have suggested that warming temperatures are changing the species of waterfowl in different regions, and these data confirm that,” said Dr. Tim Meehan, quantitative ecologist with the National Audubon Society and lead author of the paper. “The weather in winter is no longer so severe that the birds have to fly south. They stay further north and tell us that something fundamental has changed in their area. “
American Black Duck, Copyright Alan Ryff, from the Surfbirds Galleries
The data show that while the populations as a whole have not changed significantly, the frequency has changed noticeably in places that corresponded to the warming temperatures. For example, the American black duck – a species similar to the mallard with darker coloring and a distinctive purple on its wing – showed overall stable occurrence, but a marked increase in presence in traditionally colder northern locations and a decrease in traditionally warmer regions .
The results affect both ducks and humans.
“With the number of paddling and diving ducks now hibernating further north, scientists and conservation partners should determine whether the availability of winter forage in northern latitudes is sufficient to support increased numbers of winter ducks with global warming,” said Dr. Richard Kaminski, director of the Kennedy Center at Clemson University. “The local economy in traditional southern duck wintering areas may be affected by fewer hunters and bird watchers as these conservationists hunt or bird watch elsewhere.”
The decline of certain waterfowl and other waterfowl species is a major concern for communities that rely on bird watching and waterfowling. These activities generate billions of dollars nationwide each year. Southern duck hunters have already seen remarkable changes in the number of certain birds they see.
The results of this study underpin the role of community science in documenting the effects of a changing climate. The Christmas Bird Count is the longest running Community Science Bird project in the world. The count began on Christmas Day 1900 hiring volunteer observers to count birds in their area and report to Audubon. The results shape Audubon’s science for the remainder of the year and well beyond. This study was based on CBC data worth 50 years from 1969.
“It’s a testament to the power that anyone can make a real difference in scientific observation,” said Dr. Brooke Bateman, director of climate science at the National Audubon Society. “People may not have known what climate change was in 1969 when they went out on Christmas Day to record the birds they saw, but their reports are helping us solve one of the 21st century’s most pressing global problems. “
The results also underscore the research conducted by Audubon in his 2019 climate science report Survival By Degrees, which found that with rising global temperatures at current rates, two-thirds of North American bird species are threatened with extinction.
“Science shows time and time again that ignoring climate change has consequences,” said David Yarnold, CEO of the National Audubon Society. “Sometimes it’s the sentimental loss of not seeing the birds you know in your own yard, sometimes it harms an industry like tourism or outdoor recreation, and sometimes it’s a bigger cause for concern about the locations which both ducks and humans must survive. Birds tell us the changes are already here. The question is whether we are ready to respond and resolve. “
The study can be found at: https://wildlife.onlinelibrary.wiley.com/doi/10.1002/jwmg.22023