It’s a stressful time for songbirds migrating through Duluth right now. But that’s resulted in a bonanza for backyard birdwatchers.
Thousands upon thousands of birds — species such as dark-eyed juncos, American robins, rusty blackbirds, sparrows and grackles — are essentially stuck in the Duluth area, the consequence of what’s known as a migration “fallout.”
The phenomenon occurs when weather conditions change so rapidly that birds are forced to temporarily abandon their journey northward. In northern Wisconsin last week, several loons literally fell out of the sky, their wings coated with ice.
When temperatures spiked into the 70s and 80s a couple weeks ago, birds began flying north, explained Alexis Grinde, an avian ecologist with the Natural Resources Research Institute at the University of Minnesota Duluth.
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“There's an advantage for birds to get north to their breeding grounds sooner rather than later so they can get in a good territory,” Grinde said. “So as soon as food is available, and they get those cues from the weather, they start migrating north.”
But as birds were flocking northward over Duluth and along the shore of Lake Superior, winter reared its head again. Frigid temperatures and snow essentially stopped them in their flightpaths.
“They were like, ‘Uh-oh,’ and turned around,” Grinde said. “We call it a reverse migration.”
Birds retreated to the Duluth area where they found open ground to scrounge for the seeds, and anything they could use for food, to refuel for when the weather allowed them to resume their journey northward.
Grinde says it’s not unusual for some birds to layover in Duluth every spring. But this year, she said, “the amount of birds that were moving and then decided to turn around and come back was I think relatively unprecedented for this area.”
And all those birds are flocking to roadsides, backyards and birdfeeders — anywhere they can find food. Grinde said these songbirds are generally pretty docile. But at her birdfeeders, she said they’re fighting off squirrels for food.
The kinds of birds pit-stopping in Duluth are short-distance migrants. They winter in the southern U.S. and migrate to the northern U.S. or Canada.
Grinde says her research on birds that summer in the Superior and Chippewa National Forests in northern Minnesota suggests changing weather patterns may have a long-term impact on their survival.
“Their population trends are declining. And we think it has to do with the kind of volatile spring weather that we've been seeing the past 5 to 10 years, where we warm up, and then we have these late snow storms or ice storms.”
Grinde expects to see most of the birds in Duluth continue their journey north over the next few days as the weather warms. In the meantime, she said, her advice is simple — feed the birds.