Photo: The Canadian Press

Pest Control Officers Gregory Cornes, left, and Andre Pitman, both from the D.C. Department of Health's Rodent Control Division, searching the flower beds for rat burrows near U.S. Capitol building in Washington.

Andre Pittman and Gregory Cornes are on a mission to rid Washington of opportunistic vermin.

But their target isn't corrupt officials or shady political fixers; it's Rattus Norvegicus, the common Norway Rat.

The nation's capital is facing a spiraling rat infestation, fueled by mild winters and a human population boom. Washington's government is struggling to keep pace, with the pest control department fielding a record number of calls.

The pest control company Orkin ranks Washington as America's fourth "Rattiest City," based on the number of new service calls per year. That's up one spot from the previous year and just behind Los Angeles and New York; Chicago has been ranked No. 1 for four consecutive years.

While D.C. doesn't boast the subway monsters famous in New York, anecdotal evidence is piling up that the rodents are on the march. In September, a viral video showed security camera footage of a rat pulling a fire alarm , forcing the evacuation of an apartment building.

Gerard Brown, head of Washington's rodent control department, says a string of gentle winters has enabled the rodents to breed constantly. The harsh winters don't necessarily kill off the rats. Most Norway rats live only about eight months, and they stay warm by burrowing underground or chewing their way into basements. But an extended freeze would choke off their food supply, which limits the rodents' prodigious breeding. A mature female rat can give birth to one litter per month, with an average of 10 babies per litter.

Washington is also in the midst of a gentrification-fueled economic and population boom. The District's population just passed 700,000 — more than Vermont and Wyoming. Brown said the number of restaurants, bars and coffee shops has increased by 25 per cent in two years.

"More people with more money means more restaurants, which means more garbage, which means more rat food," Brown said.

In several ways, Washington is perfectly suited for the critters. It is filled with green space, from the National Mall to the many signature traffic circles; Dupont Circle is apparently a hot spot.

Rats also love waterfront areas, and part of Washington's gentrification boom has focused on the Navy Yards or the new Wharf Marina — presenting the ultimate rodent attraction of a flourishing waterfront restaurant scene.

This isn't even Washington's first war on rats. Former Mayor Anthony Williams referenced rat problems in his inauguration speech in 1999. Back in 1967, a rat gnawing on power station wires knocked out electricity for nearly an hour in about a third of Washington.

This time, Mayor Muriel Bowser has allocated an extra $900,000 to boost rodent control efforts and increase staffing. The government is also offering financial assistance and incentives for restaurants to buy mini-trash compactors that fit in urban alleyways and limit the rats' access to food.