Millions of birds are expected to fly over Michigan Thursday and Friday nights as spring migration reaches its peak, according to the Michigan Audubon.
Max Henschell, research director for the organization, said migration activity has intensified across the state in recent days, with orioles, Ruby-throated hummingbirds and dozens of warbler species now arriving in large numbers.
Researchers with Purdue University’s AeroEco Lab are predicting between 9 million and 10 million birds could cross Michigan skies each night Thursday and Friday, prompting a high alert for “Lights Out” efforts aimed at reducing artificial light pollution.
Henschell said most migratory bird species travel at night and rely on the moon and stars to navigate.
“When there’s artificial light, that really can disorient the birds,” he said. “It causes them to expend a lot of the energy that they really need for migration.”
Bird advocates are encouraging residents and businesses to turn off unnecessary outdoor lighting overnight to help reduce bird deaths and exhaustion during migration.
The migration surge also means birdwatchers across Michigan could see an increase in colorful species this weekend. Henschel said recent sightings in the Lansing area have included more than 20 species of warblers, along with scarlet tanagers and great crested flycatchers.
Some less common birds have also appeared in Michigan this spring, including summer tanagers, which typically breed farther south.
Henscheli said cooler temperatures and northern winds have slightly delayed migration timing this season, but warmer weather forecast later this week should help birds move through the region more quickly.
Wildlife experts are also reminding residents to keep cats indoors during migration season because domestic cats are a major source of bird mortality.
They also recommend keeping bird feeders clean during migration season to help prevent the spread of disease.
Michigan Audubon is also holding its annual Birdathon fundraiser to support research operations at Whitefish Point Bird Observatory in Michigan’s Upper Peninsula.
Henschell encouraged bird enthusiasts to report sightings through the free eBird app, a community science platform managed by the Cornell Lab of Ornithology.
“That data is used by Cornell, and we use some of that data as well to help understand bird migration through Michigan,” he said.
Michigan's bird migration wraps up at the end of May.