Monarch Butterflies Making Their Way To Chicago Area

WILL COUNTY, IL — Spring is here and that means all things birds, bugs and butterflies are making their way north. Monarch butterflies are on their way for their spring migration, and they have been spotted in Illinois and bordering states, according to a release from the Forest Preserve District of Will County.

You can chart the progress of the Monarchs based on reported sightings from citizen scientists thanks to a map from Journey North. The first reported sighting verified with a photograph in Illinois this year was on April 14 in Columbia, Illinois, just outside St. Louis, according to Journey North.

There was also a reporting of a Monarch on April 6 in Warrenville. Sightings have also been reported in Missouri and Tennessee in recent days and weeks, a sure sign they are getting ever closer to Will County, the preserve said.

Historically, the first sightings in Will County come sometime in May, although in some recent years they have arrived as early as mid-April, the preserve said.

Program coordinator Suzy Lyttle said each year's migration can vary depending on the weather conditions they encounter along their journey. They're much more delicate than birds, she said, and they can't fly in the rain. Winds also can make a big difference. They normally can fly at speeds up to 20 mph, and favorable wind conditions can allow them to travel anywhere from 40 miles to 100 miles per day.

"From year to year, things change," Lyttle said of their annual trek north. "It just depends. Some years they're early, and some years they're late."

The monarchs we see in Illinois overwinter in the oyamel fir forests of Mexico, according to the preserve. There are two monarch populations in the United States: the eastern population and western population. Ours is the eastern population, and it includes all monarchs east of the Rocky Mountains. The smaller western population is found west of the Rockies and overwinters in California.