As the snowy months approach, many pack up and head south for the winter, leaving the cool Chicago weather behind.
That includes hummingbirds -- and according to experts, they start their migration long before the cold weather hits.
According to a post from the Chicago Botanic Garden, hummingbirds are often found in the Chicago-area yards during the late spring and early summer, when female birds build "golf-ball size nests" made from bits of soft leaves and spiderwebs. But by September, they're already on their way out as part of the birds' "great fall migration."
"Hummingbirds tend to be out of the Chicago area by about the second week in October," the post reads. "On their fall migration south, they either cross the Gulf or follow the Texas coast back to Mexico."
Feeling out of the loop? We'll catch you up on the Chicago news you need to know. Sign up for the weekly Chicago Catch-Up newsletter here.
And while there are more than two dozen hummingbirds in the United States, it's the ruby-throated hummingbird that you might find in your Chicago-area backyard.
"The ruby-throated is the only hummingbird regularly found east of the Mississippi River," the garden says. "During the summer, they are frequent residents at the Chicago Botanic Garden. Right now, many more are coming from Canada, stopping in search of nectar and insects. They’re building up energy for their long journey south" for the winter season.
Hummingbirds are typically in Illinois from May to October, though a scattering of them have been seen as early as March, according to the Forest Preserve District of DuPage County. You might have noticed them by the "hum" of their flapping wings, or their chatter, which sounds like high-pitched dolphin chatter," the Forest Preserve says.
As for looks, they're hard to missed. "Ruby-throated hummingbirds are bright emerald or golden-green on the back and crown, with gray-white underparts," the Forest Preserve continues. "Males have a brilliant iridescent red throat that looks dark when it’s not in good light."
Hummingbirds aren't the only Chicago residents heading south for the winter. Butterflies are, too.
Dubbed as the "monarch migration," the spectacle sees the winged insects embark on a months-long journey to Mexico, Doug Taron of the Peggy Notebaert Nature Museum says. The butterflies will pass through Chicago, the Mississippi Valley and Texas before setting up camp about 100 miles west of Mexico City, Taron says.
Typically, an abundance of butterflies can be spotted throughout September, with peak monarch migrations in the area falling Sept. 5-10, Taron noted.
Taron said there have been reports of butterfly clusters in central Michigan, which is an indication that the creatures "are definitely coming."
Chicagoans will be able to make out bundles of butterflies well into October, too, as Taron said groups of stragglers are expected to round out the migration.