Millions of birds representing over 350 species migrate through Michigan on their way south for the winter. The birds have to cover thousands of miles to reach their destinations, rest, and find food and shelter along the way. They also have to contend with buildings that can be deadly.
In early October, nearly 1,000 migratory birds died after flying into a single building in Chicago. The mass mortality event claimed the lives of many songbirds—including warblers—that likely flew through Michigan, according to ornithologists. As many as 1 billion birds die each year in building collisions, according to the American Bird Conservancy.
Michigan lies at the intersection of two of the major "flyways" in North America: the Atlantic and the Mississippi. Charlotte Probst is a researcher at the University of Michigan's School for Environment and Sustainability. She explained that birds from some parts of the flyways will often fly through Michigan so they don't have to cross the Great Lakes.
"Michigan is really cool; as birds are traveling, a lot of times they'll get funneled through Michigan because we're kind of like this peninsula," Probst said.
Andrew Farnsworth is a visiting scientist at the Cornell Lab of Ornithology. "Michigan sits in a position where every fall, something on the order of 350 million birds pass through the state. It has a key role in the whole system," Farnsworth said.
Experts say that groups of migrating birds are drawn to densely constructed areas because of artificial light at night; once they are in these areas they can become disoriented and often fly into reflective glass windows in the daylight.
"Simply stated, birds do not know that glass is a solid barrier. They do not know the difference between a tree reflected in a pane of glass and the tree itself," said the Michigan Audubon.
Probst and Farnsworth said that while turning lights off at night is important for migrating birds, home and building owners can also treat their windows to make them less reflective to birds. Farnsworth explained that there are different types of glasses that are less reflective, but that treatments can be as simple as putting tape or decals on either side of the window for the birds to see. Even paper dots placed in lines can deter birds from colliding with windows.
"From an individual perspective—thinking globally and acting locally—that kind of approach...that's something that's as easy to do as a flick of a switch to turn off lights: treat your windows," Farnsworth said.
Keeping pet cats indoors benefits migrating birds, too: one study found that cats are responsible for 1 to 4 billion bird deaths per year. The National Audubon Society says that planting native vegetation is another way to help migrating birds, who need plenty of food to make it on their journey.
"There are different ways that you can do positive things," Farnsworth said.
Probst said migrating birds would be much safer if people simply turned off lights at night and added visual cues for birds on their windows. "So many things are impacting wildlife that the solutions feel really insurmountable sometimes...but this solution is actually kind of simple. It just takes organizing, and it takes getting people to care."
Farnsworth said that getting folks to care about migrating birds in the first place is the first step towards protecting them.
"The bottom line: this does come down to things you can see as a human...look up, listen...it's super important. If you're not already interested in birds, you will be if you open your eyes and ears."
