An extended family romped in Lafayette Square across from the White House, running along the brick sidewalks and hiding in the bushes. For their moonlit dinner, there was pizza, candy and soda.
Visitor Bill Hudson found the scene horrifying.
"There have to be hundreds of rats in there," said Hudson, who works for a Maryland food distribution business. "I regularly take visitors through the park at night, done it for years. Now I'll have to say, `I'll show you the White House, and you can do hurdles over the rats.' "
The mild, wet summer has created ideal conditions for rat colonies to expand. Pleasant days mean more picnickers leaving tasty garbage behind, and rain keeps the food soft and attractive, specialists on rat behavior say. Across the city, in commercial and residential neighborhoods as well as in parks, the Norway rat population appears to be on the rise, according to some who keep watch.
Earle Kittleman, a spokesman for the National Park Service, confirmed that there are many more rats than usual in Lafayette Square. The annual autumn rat eradication program will become a summer program this year, he said.
"There's a definite upswing," he said. "They're going to start the applications" today.
Kittleman said the Park Service uses a poison approved by the Environmental Protection Agency. The poison is placed in small boxes and positioned so that rats following their regular routes will run through the boxes. Upon finding the bait, they'll eat it.
But people food is what the rats have been eating. One night this week in Lafayette Square, trash cans were full of treats: a slice of pepperoni pizza, a half-eaten egg-salad sandwich on dark bread and plenty of spilled sodas. Peanuts littered a walkway.
Fine dining for rats.
"They like what we like," said Harold Harlan, a consultant with the National Pest Control Association. "Spicy food doesn't bother them at all. If we eat it, they'll eat it."
And that's the basis of the problem. Unless humans are eradicated, there always will be a supply of food for rats, Harlan said. An increase in the supply, without an increase in predators, means an expanding population, he explained.
Federal and city officials have good reason to continually work to contain the rat population. Rats spoil food by their contact, spread disease through the fleas they harbor and quickly can overrun a territory they like.
A female Norway rat is sexually mature at three months and can produce and nurse a litter about every seven weeks, Harlan said. Each litter contains about seven young. Rats are social animals, and an expanding colony often will stay close together, adding new burrows next to old ones.
In Lafayette Square, in the grassy area at the base of the Andrew Jackson statue, there are 18 burrows.
Although federal authorities have seen an increase in rats in Lafayette Square, city officials say they have not detected any similar surge in rats in the residential and commercial parts of the city.
Frankie Cox, chief of the city's rat abatement office, said Metro construction and major house renovations can displace rats. She said her office has seven people in the field responding to complaints and checking places where rats seem to return.
The city uses a chemical substance that acts as a deadly blood thinner that is sealed in small boxes and plugged into rat holes. The box blocks the burrow, and the rat has to chew through the box -- and the bait -- to get out. Cox said the smarter rats kick the boxes out of the holes to get to their usual food supply.
Unless the garbage that attracts rats is eliminated, Cox said, there isn't much chance of getting rid of the rodents.
As for complaints that there are more rats, Cox had a novel explanation:
"We always say there are two rats for every person in the city," she said. "The [resident] population is declining, so maybe there are three rats per person now." Census figures put the District's human population at about 580,000.
Counting rats always is guesswork. Although some venture out in the open, many more are hidden from view in burrows. Harlan said the generally accepted, but unscientific, rule for counting a rat population is to multiply by 10 the number seen in public. Only the bolder ones will come out when humans are around, he said.
If that's the case, there are about 500 rats in Lafayette Square alone. Fifty were seen Wednesday night scampering around the base of the Jackson statue and skittering across the sidewalks on the west side of the park.
For San Brown, the multiplication rule would mean there are nine rats lurking around her Shaw house in addition to the one she spotted recently.
"It was the first time. Never, ever before," she said. "We got rid of it, but we know there are lots more outside. They are so comfortable here, they come out in the daytime."
Henry Jenkins, 65, who is retired and lives in Riggs Park in Northeast Washington, said he also is seeing rats for the first time. This summer, he quit mowing the vacant lots across from his Fourth Street brick rambler and called on the city to take up the chore. They failed to respond, he said, and now rats run among the tall weeds.
Weeds aren't enough to attract rats; they need food. According to Jenkins, that's supplied by a group of men who sometimes hang out in the area and leave garbage behind. On Friday, rat holes and discarded french fries, hamburger scraps and partially filled soda cans were visible not far from the street.
"It's an eyesore and a health hazard," he said. "There are rats there for sure."
Conception Picciotto, who has maintained a peace vigil in Lafayette Square for 17 years, has encountered rats on a more personal level.
"A few nights ago, I dozed off for a few minutes and felt something on my hand," she said. "I looked. It was a rat, and I screamed."
Picciotto said she throws her bedroom slippers at the uninvited guests to get them to leave her alone.
"They are everywhere," she said. "They are disgusting."