If you’ve been outside lately, chances are you’ve already heard a few new bird songs. Robins, Finches and Red-winged blackbirds are all calling out to let you know it’s the start of spring migration.
But the best is yet to come.
To learn why birds migrate, and what makes Wisconsin a special place to see migratory birds, Lake Effect’s Xcaret Nuñez spoke with Aubrey Fulsaas, a naturalist and the Children’s Events Coordinator at the Schlitz Audubon Nature Center, for this month’s episode of Chirp Chat.
Why do birds migrate?
Every spring and fall, the night sky is filled with millions of birds trying to make the long, arduous journey between their summer breeding and wintering grounds.
At least 4,000 bird species are regular migrants, which is about 40% of the world’s total number of birds, according to the National Audubon Society. In North America, most bird species migrate to some extent. In Wisconsin, more than 300 bird species will stop through the state during their migratory journey.
Fulsaas says the change in temperatures doesn’t necessarily trigger birds to migrate, but rather the amount of resources they have available to them, such as food and nesting sites.
“A lot of our insect eater [birds], they leave Wisconsin in the winter because their food disappears — their insects are gone in the wintertime," Fulsaas says. “[Birds] come back once the bugs come back and we have great nesting locations they can take advantage of. If they all stayed down in the tropics, they'd be overrun, there wouldn't be any real estate available. So [birds] come back and find a place to nest up in the northern hemisphere by us.”
How birds navigate migration
Some migrating birds can travel thousands of miles in their yearly travel, and for the most part, they don’t veer off course. But Fulsaas says scientists are still not entirely sure how birds navigate migration. She says some indicators birds are known to use are geographic markers, like the Mississippi River and the Great Lakes.
These geographic markers create pathways called flyways that birds use to help them make their migration journey. Of the four flyways, Wisconsin falls in the Mississippi Flyway, which is used by about 325 bird species and roughly 40% of shorebirds and waterfowl in North America.
But not all birds use a flyway to navigate migration — Fulsaas says there are several ways birds can use their senses to stay on track and it also depends on the type of migratory bird they are.
“Some birds will use the sun, and a lot of birds actually migrate at night and use the stars to help them find their way,” Fulsaas says. “There's research that says the Indigo bunting uses the North Star to find its way when it's migrating. [Birds] know the parts of a compass by also sensing the earth’s magnetic fields.”
Some neat migratory birds visiting Wisconsin
“In March, the males come back first to claim their territories,” she says. “Then the females come back later once the bugs are out a little more, and then she'll play a little game of Bachelorette and pick what territory she wants to go to.”
Fulsaas says Golden-crowned kinglets have already been seen fluttering around pine trees in Milwaukee. The tiny songbird is known for its high-pitch calls and uses its small bill to pluck bugs off coniferous trees. The male kinglet flashes its gold-orange crown when it’s excited, otherwise, it's usually hidden.
“The pinnacle of spring migration to a birder is warbler migration,” Fulsaas says. “Warblers are these tiny Neotropical birds, and they winter down in Central and South America and come up through that flyway. The beauty of them is that there are so many different types. We have recorded 36 different kinds of Warblers at Schlitz Audubon Nature Center. They're very colorful — they come in vibrant yellows and some have a little bit of green, some of them have orange, and they're just really fun birds to watch.”
Fulsaas says peak Warbler migration in Wisconsin is usually around the end of April through the beginning of May. She adds that the migration activity of Warblers and other bird species can be tracked by using tools like Birdcast.
How to care for visitor birds
Birds make various stops along their flyway route, often called stopover sites, where they rest and find food. Fulsaas says some sites are like gas stations where birds quickly stop to refuel, and other sites are more like a bed and breakfast where birds stay for days to weeks.
“Make your backyard a great bed and breakfast for birds!” Fulsaas says. “Have water available for them and have different types of food. Sometimes the birds migrating through might be more interested in eating bugs or fruit. So you can have a good diversity at your bird feeders for them to grab a nice bite to eat. Have some good shelters for them and have some native plants that they can live in and just kind of rest on their journey.”
Fulsaas says another way people can help care for migrating birds is by turning off the bright lights in large office buildings at night.
“Especially in buildings like skyscrapers, really big business buildings that are leaving their lights on overnight,” she says. “It really confuses [birds], especially if they're trying to track [their migration flight] using the stars. So a lot of fatalities happen when they run into those lights at night.”
Chirp Chat’s Bird of the Month for April
[The Baltimore oriole] is a blackbird with this beautiful, bright orange plumage that’s unlike pretty much any other bird we see in Wisconsin… It's just absolutely mesmerizing,” Fulsaas says. “Usually, if you're hanging out here at Schlitz Audubon Nature Center, in late April, early May, if you hear this beautiful, bright whistling noise, and you look up, you'll see this orange bird just sitting up in the tree.”
Fulsaas says the Baltimore oriole spends winter in Central America and enjoys hanging out near forests where coffee and cocoa trees grow and eats lots of ripe fruit.
To attract this bright, tropical bird to your yard, Fulsaas says people can simply slice an orange and stick it on a stake by their bird feeder. She says a memorable saying birders often say is “Oranges for orioles!”
