Chicago’s tallest skyscrapers have gorgeous, sweeping views of the city that can’t be beat. Except maybe this season, when those views will be obscured somewhat by thousands of flying spiders.

A photo of a flyer distributed to guests at the Hilton’s Magnificent Miles Suites hotel posted on Reddit’s Chicago page Thursday requests guests to keep their windows shut “to avoid the annual migration of high rise flying spiders”:

“Lake shore high-rises, Willis Tower and John Hancock are noticing the annual influx of flying spiders spinning mini-masterpieces as high as 95 stories.” the note reads, later explaining that “In natural environments, these spiders live on rocks overhanging water. In the city, they have found the next best thing; tall buildings and high-rises.”

The spiders, formally named Larinioides sclopetarius, spin balloon-like contraptions from their silk and ride lakefront air currents to out-of-the-way crevices, where there is ample food, the Hilton note explains.

Chicagoist confirmed with Hilton Suites Chicago General Manager Patrick Filatre that the hotel does issue this warning during prime flying spider season each year.

The Field Museum’s Jim Louderman, a collections assistant for insects, told the RedEye that the spiders, which are about the size of a half dollar when fully grown and can be found all over the U.S., are less venomous than a bee, and they don’t bite humans.

Have you caught a glimpse of these spiders while hanging out in Chicago’s upper levels? Tell us about it in the comments.

Flickr photo by saturn a.