How Construction Projects Have Made Denver One of America's Rattiest Cities

Denver finds itself on plenty of top-ten lists — registering first, for example, on the U.S. News & World Report roster of best places to live earlier this year.

But its appearance on a new list from Orkin is unlikely to be touted in any Visit Denver brochures. The pest-control giant has just released its compendium of the "Top 50 Rattiest Cities," with the communities ranked by the number of rodent treatments the company performed between October 1, 2015, and September 30, 2016. And, yes, the Mile High City is among the ten towns that put out the most calls to Orkin men and women.

Why did Denver place above urban areas such as Boston, Dallas, Cleveland, Atlanta and more, as seen in the complete list below? Ryan Riley, Orkin branch manager for the Denver area, offers a variety of reasons. But arguably the biggest pertains to the development boom in the city during recent years.

"Whenever you have new construction, whatever was living there before you started building has to go somewhere," Riley says.

The "rattiest cities" label is broader than it seems at first blush; Riley notes that calls for both rats and mice were included in the overall count. In addition, cities where Orkin has the largest footprint business-wise tended to score best, and the company is very well established in the Denver metro area.

As for the Denver neighborhoods that have the most rodent trouble, Riley declines to get overly specific for competitive reasons. But "according to our records," he says, "the service locations we've been going out to are more in the downtown areas and your historic neighborhoods, and also places near waterways, like the Platte River. You're going to find a lot more rodent activity in those places because food, water and shelter is available."

Rats tend to be more common near water sources, and they're not always content to stay at ground level. Whereas residents of areas such as Los Angeles are familiar with creatures known locally as tree rats, Riley says, "we call them roof rats here. They typically like to occupy the attics of buildings. But if you have a high population of rats somewhere, you may see one run across a tree branch to get into another building. That's why we tell homeowners to trim back their trees from their houses. If a branch isn't touching a building, that limits the highway onto your roof in the first place."

Granted, branch-cutting doesn't eliminate the possibility of rats reaching the upper levels in homes. As Riley points out, "some rats can climb walls."

Whereas rats live in burrows, "mice can be anywhere and everywhere," Riley says. "All they need is a hole the size of a dime to get in — and if you see one mouse, you're probably going to see more. A rat needs a hole about the size of a quarter."

Such gaps are a particular problem for folks living near construction sites, whether they're in the city proper or out in the 'burbs.

"Say a developer is building in an open field," Riley says. "Nothing's been disturbed for years upon years, and when they dig up the earth, things are going to run. Now, most of the time, new buildings are sealed up very well, and residents may not notice rodents on the interior — but they may notice them on the outside. And if the mice or rats can't get into the new building, they may look for gaps in other homes or buildings nearby."

He adds that "whenever you see new construction, and more people moving in, it means we're occupying more space that's being disturbed — and that relates to the number of calls we get in downtown Denver and historic neighborhoods," where there can be multiple construction projects on the same block.

The overall volume of calls tends to go up around this time of year, "because that's typically when we get the first snows," Riley allows. "When that happens, we gear up. Rodents are mammals; they don't hibernate. All they do is move to better places, like your home, your building."

What can homeowners — especially ones near construction projects — do to prevent a rodent invasion? Riley recommends sealing up any and all holes, no matter how small, evaluating doors and windows to make sure they're properly weather-stripped, being careful to keep patio doors or screen doors closed, properly storing and sealing garbage, and not leaving anything stacked against the outside of the building that can provide shelter for little (or not-so-little) fur balls.

Still, the danger of unwanted rats and mice persists in rapidly transforming Denver. "Downtown, you see a lot of cranes going up, lifting, taking care of new developments," Riley says. "And when you see that, you can bet that rodents are looking for somewhere else to go."

Continue to see Denver's place on Orkin's list of the rattiest cities in America.

Here's the company's list of the U.S. cities that have logged the most rodent calls over the past year.

Orkin's 50 Rattiest Cities

1. Chicago
2. New York
3. Washington D.C.
4. Los Angeles
5. San Francisco-Oakland-San Jose
6. Baltimore
7. Philadelphia
8. Minneapolis-St. Paul
9. Detroit
10. Denver
11. Seattle-Tacoma
12. Boston
13. Miami-Ft. Lauderdale
14. Dallas-Ft. Worth
15. Cleveland
16. Atlanta
17. Hartford & New Haven, Conn.
18. Pittsburgh
19. Indianapolis
20. Portland, Ore.
21. Houston
22. Raleigh-Durham, N.C.
23. Milwaukee
24. Norfolk-Portsmouth-Newport News, Va.
25. Richmond-Petersburg, Va.
26. Albany-Schenectady-Troy, N.Y.
27. Charlotte, N.C.
28. St. Louis
29. Buffalo, N.Y.
30. Kansas City, Mo.
31. Tampa-St. Petersburg, Fla.
32. Sacramento-Stockton-Modesto, Calif.
33. Grand Rapids-Kalamazoo-Battle Creek, Mich.
34. Cincinnati
35. Rochester, N.Y.
36. West Palm Beach-Ft. Pierce, Fla.
37. Columbus, Ohio
38. New Orleans, La.
39. Nashville, Tenn.
40. Greenville-Spartanburg-Asheville, S.C.
41. Flint-Saginaw-Bay City, Mich.
42. Albuquerque-Santa Fe, N.M.
43. Portland-Auburn, Maine
44. Green Bay-Appleton, Wis.
45. Phoenix
46. Orlando-Daytona Beach-Melbourne, Fla.
47. San Diego
48. Burlington-Plattsburgh, Vt.
49. Madison, Wis.
50. Salt Lake City