CHICAGO (CBS) — Just in time for Halloween, the rats are out wandering the city.

For the third consecutive year, Chicago ranks at the “rattiest city” on Orkin’s ‘Top 50 Rattiest Cities’ list.

In fact, service calls in Chicago are up 32 percent.

“It does surprise me. Chicago has quiet a number of conducive conditions of its own and a lot of opportunity for improvement,” said Orkin Entomologist and Technical Director of Orkin’s Midwest Region, John Kane.

“Chicago certainly has a lot of mice and rat pressure. We have a lot of square mileage spread out and we also have quiet a lot of alleys in which we put our garbage.”

New York is a close second, followed by Los Angeles and San Francisco, he said.

Kane said as the weather gets colder, unwanted pests like mice and rats look for food, water and shelter to survive the winter.

“Rats and mice begin looking for warmer, more insulated places to get through the winter, and these too often happen to be our homes or businesses,” Kane said. “Rodents like to chew on wood and electrical wires, increasing the fire danger behind your walls and potentially damage to your home.

“Rats can squeeze through a hole the size of a quarter, while mice can fit through a hole the size of a dime. Even if they can’t find an opening, they can often chew their way in.”

Mayor Emanuel has proposed spending an additional $1.5 million next year to get rid of rats.

The rankings are based on the number of rodent treatments the company performed from Sept. 15, 2016 – Sept. 15, 2017, including both residential and commercial treatments.

Orkin’s full list of the Top 50 Rattiest Cities include:

1. Chicago

2. New York

3. Los Angeles

4. San Francisco – Oakland

5. Washington, DC

6. Philadelphia

7. Detroit

8. Baltimore

9. Seattle – Tacoma

10. Dallas – Ft. Worth

11. Denver

12. Minneapolis – St. Paul

13. Cleveland – Akron

14. Atlanta

15. Boston

16. Hartford – New Haven

17. Portland, OR

18. Miami – Ft. Lauderdale

19. Indianapolis

20. Houston

21. Milwaukee

22. Pittsburgh

23. New Orleans

24. Cincinnati

25. Richmond – Petersburg

26. Sacramento – Stockton

27. Kansas City

28. Charlotte

29. Norfolk – Portsmouth – Newport News

30. Buffalo

31. Columbus, OH

32. St. Louis

33. Raleigh – Durham

34. Grand Rapids – Kalamazoo

35. San Diego

36. Albany – Schenectady

37. San Antonio

38. Tampa – St. Petersburg

39. Rochester, NY

40. Nashville

41. Champaign – Springfield – Decatur

42. Greenville – Spartanburg

43. Memphis

44. Phoenix

45. Syracuse

46. West Palm Beach

47. Orlando – Daytona Beach

48. Madison

49. Flint – Saginaw

50. Green Bay – Appleton