LANSING — Rising global temperatures are negatively affecting numerous bird species, scientists say
Michigan Audubon says rising temperatures are a dire threat to more than 50 highly vulnerable bird species across the Midwest.
At the current rate of increase, as soon as 2050, “Michigan will likely experience rapid and uncertain Great Lakes water level fluctuations, stronger storms, harsher droughts and increased heat-related illnesses,” according to the organization’s website.
Rising temperatures create problems for migratory birds, especially during the fall, and birds that eat insects are particularly at risk.
“Because there are more insects out later in the year, there’s not a pressure for those species to move,” Max Henschell, the research director at Michigan Audubon in Okemos, said.
Staying in the Midwest too long disrupts breeding schedules, changing when eggs hatch and limiting the birds’ ability to feed chicks, he said.
It is difficult to track year-to-year data on the effects on migration based on temperature changes, so experts must look at broader patterns, he said.
“Long-term patterns that we’re starting to see are part of something called ‘protracted fall,’ which is when migration gets longer,” Henschell said.
Certain species are at a higher risk, such as the American robin, he said.
“We potentially might have robins in the Lansing area all year-round. They’re just not moving out of the area because there’s no lack of food availability, particularly in warmer years,” he said.
Other species that are hanging around Southern Michigan year-round include bluebirds and sandhill cranes.
In addition, some neotropical birds that migrate from South America to northern states are being affected by “mismatching between when there is peak food availability and when the birds are arriving on their breeding grounds,” Henschell said.
“This causes consequences for long-term populations and nestlings,” he said.
Aside from climate change, other factors pose threats to bird habitats, experts say.
For example, “some invasive plant species are taking over areas and reducing available habitat or changing necessary conditions that a lot of species need,” he said – although that cannot be attributed to climate change specifically.
Among other factors are changes in land cover, clearing of forests and loss of grassland habitats, he said. Those changes are human-inflicted, he said.
Climate change has also contributed to physical changes in bird species, research shows.
For example, a 2019 University of Michigan article quoted researcher Brian Weeks, now an associate professor in the School for Environment and Sustainability, saying, “We had good reason to expect that increasing temperatures would lead to reductions in body size, based on previous studies.
“The thing that was shocking was how consistent it was. I was incredibly surprised that all of these species are responding in such similar ways,” Weeks said.,
The same article quoted researcher David Willard, an ornithologist at the Field Museum in Chicago, saying, “When we began collecting the data analyzed in this study, we were addressing a few simple questions about year-to-year and season-to-season variations in birds.
“The results from this study highlight how essential long-term data sets are for identifying and analyzing trends caused by changes in our environment,” he said.
Questions about this story? Contact Capital News Service Editor Eric Freedman at freedma5@msu.edu
