It’s a ‘spider fest’ atop Chicago skyscrapers

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The top of the Hancock Tower is “like a haunted house,” says a facilities manager. | John J. Kim~Sun-Times file

Updated: January 23, 2012 3:19AM

At this time of year, there’s no shortage of fake spider webs around town as people try to make their houses look haunted.

But in the city’s highest reaches, there’s no need for the fake stuff.

Skyscrapers are prime real estate for the creepy crawlers of the city — with the bugs often riding wind currents high into the sky.

At the top of the John Hancock Center, it’s a “spider fest,” says Mead Elliott, the building’s broadcast facilities manager.

“They are crawling everywhere, they are coming down on their strings everywhere, there are a lot of dead carcasses around — it’s like a haunted house,” he said. “It’s really weird seeing so many. You scratch your head, literally and figuratively.

“When I first started, there was a lot of night work and all of sudden you have three or four of them crawling in your hair. As time goes on, you become more aware of them and can brush them away.”

Elliott said workers have tried various methods to control the spiders in the past, but nothing really works — they always come back.

“We often think of the top of the building as this sterile environment of steel and glass, but really it’s surrounded by insects,” said Steve Sullivan, curator of urban ecology at the Peggy Notebaert Nature Museum.

Acting somewhat like mountains, skyscrapers can create drafts that suck air — and bugs — to the top of the structures. For spiders, that means there is plenty of food up there.

“We have pumped these insects literally up the side of the building,” Sullivan said. “By this time of the year, [spiders] just build webs everywhere.”

So how do the spiders end up outside a window on the 95th floor?

Sometimes they just crawl. Most spiders, though, will use a technique called ballooning, which allows them to “fly” for miles.

“They let out a little bit of silk, catch an uplifting air current and then sail in the current, basically like flying a kite,” said Petra Sierwald, associate curator of insects at the Field Museum.

Many of these spiders are from the orb-weaver family, which includes a number of different species that range in size. Some young are as small as a punctuation mark while adults can grow to about an inch big.

Once a spider is planted on the side of the building, its silk is so strong that it is barely affected by wind or rain — even if the little creature is hundreds of feet in the sky.

“If there is any danger, there are an enormous number of crevices and cracks, and they will just go in there and squeeze in,” Sierwald said.

The Willis Tower runs a window washing system every day, weather permitting, which helps keep the spiders at bay, according to Gary Michon, general manager of U.S. Equities Asset Management, the managing agent for the property.

“It’s more of a nuisance to the tenants,” Michon said of the spiders. “They are paying for great views; the last thing they want to do is look out their window and see a big web.”

Wildlife experts, however, urge people to take advantage of the opportunity to observe the spiders, which are harmless to humans.

“Spiders are particularly cool because they are building architecture with one of the strongest, most resilient substances that we know of,” Sullivan said. “See how it works. It’s a cool way to get involved with nature even up on the 90th floor.”

ChicagoWildlifeNews.com