We hope you enjoyed this year's mild winter, Chicago, because this summer, spring and fall, we're going to pay for it.
Sharp drops in temperature that usually hit temperate regions in the winter naturally increase the rats' mortality rate and reduce the speed with which they breed, John Meaney, director of environmental services in Boston, where they're seeing the same phenomenon, told the Boston Globe.
Additionally, warmer weather means more people outside, discarding more trash and food that feeds urban rat populations.
In Chicago, he city's 311 center saw a 28 percent spike in reports of rat sightings this year, with 15,895 calls received through the end of July compared to 12,375 during the same period in 2011, according to the Chicago Tribune. That increase comes in spite of improvements to the Department of Streets and Sanitation's response team and a 19 percent increase in cases where rat poison was distributed to curb population growth.
The warm weather added to an already growing problem of rising rodent populations in Chicago. Last year union officials warned that cuts to local forestry and rodent control services could lead to an infestation, a charge then-Mayor Richard Daley rejected, according to NBC Chicago.
Rat poison has been a controversial method of curbing the city's rodent problem in recent years after multiple instances of pets ingesting the toxic substance and similar squirrel poison, which resembles ground beef.
Chicago's 47th Ward recently launched a pilot program with the Tree House Humane Society where neutered, vaccinated and microchipped feral cats are being sent back out to the streets to try and deter pesky rodents.