CHICAGO (STMW) — The rats are coming — poking their twitchy little noses underneath porches, beneath doors, even inside airport hangars.

Several area pest-control businesses say they’ve seen a spike this year in calls for rat removal — because rodents, like people, don’t care for the bitter cold.

READ MORE: Student And Staff Data From Area School District Were Dumped On The Dark Web, And Parents And Staffers Had No Clue

“The ground is frozen hard. They can’t make their burrows on the outside,” said Carl Easter, owner of Logan Square Pest Control. “They want to come inside.”

Easter, who has been in business for 25 years, said he’s seen about a 50 percent increase in calls so far this year compared to the same time span last year.

Ditto for Sergio Valdez, owner of Anti Pest Chicagoland on the Northwest Side.

“They go to the soft spots around building structures,” Valdez said.

One rat catcher, who didn’t want to be quoted, said the Lincoln Park and Wrigleyville neighborhoods have been particularly busy — partly because posher neighborhoods tend to have lots of garbage disposal units spitting out especially tasty trash.

Easter’s work has included trapping rats at airplane hangars at O’Hare International Airport, he said.

“We’ve moved 10 out in the last 20 days at O’Hare,” he said last week. “That’s very uncommon, so many at one time.”

READ MORE: Chicago Weather: Cold Front On The Way

A rat needs about an inch of space to squeeze its body underneath a door.

“Rats’ bones are very soft,” said Easter, who prefers to trap and release — rather than exterminate — rats. He says he typically drops them off at local parks.

“They are God’s creatures,” he said. “I have a pet rat. He’s white. His name is Charlie.”

Just to be clear, the city doesn’t want to see Charlie or any other rats enjoying park facilities.

“The City of Chicago prohibits the releasing of rats into parks or public areas, with fines ranging from $1,000 to $,5000, as rats pose a public health risk and are a public nuisance,” said Molly Poppe, a spokeswoman for the Department of Streets and Sanitation. “Residents should contact 311 if they witness anyone releasing rats, or for rodent baiting requests in yards, alleys or other public ways to ensure proper abatement.”

Typically, the city doesn’t deal with rats that have scurried inside or under homes, Poppe said. City rat catchers focus on those congregating outside, and Poppe said they’ve seen a big drop in calls to 311 — about 60 percent — so far this year compared to the same period last year.

Is that because of the cold? Partly perhaps, but Poppe said the city has put a big effort into “preventative baiting” at historically rat-popular locations.

“Our main focus is baiting rats before they’re in the houses,” Poppe said.

MORE NEWS: Protesters Say Benet Academy In Lisle Rescinded Lacrosse Coach's Job Offer Because She Is A Lesbian

(Source: Sun-Times Media Wire © Chicago Sun-Times 2014. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)