Every winter, Pakistan’s capital is overrun by what is many Muslims’ worst nightmare: the sounds of screeching wild pigs. The boars seen above were photographed elsewhere in Pakistan, but are the same kind as those found in Islamabad. (Courtesy of Pakistan Wildlife Foundation)

Every winter, the capital of Pakistan’s Islamic republic is overrun by what is many Muslims’ worst nightmare: herds of screeching wild pigs.

Motivated by hunger, the reviled animals descend each night from neighboring hills to feed on the garbage bins of Islamabad’s most exclusive addresses — from high-end hotels to the city’s embassies and even the president’s residence. On their way to feeding grounds, pigs cause traffic accidents and send locals hurrying for cover. Some Islamabad residents have reportedly been injured or even killed by belligerent hogs.

Over the years, Islamabad’s Capital Development Authority has attempted to stem the flow of swine through trapping and poisoning, and up until last year it awarded pig-specific hunting licenses. Still, the local porcine population has continued to rise unabated. Now Islamabad officials have all but given up trying to contain the intruders.

“The distribution is expanding because no efforts are undertaken to control this menace,” said Abdul Aziz Khan of the Pakistan Wildlife Foundation. “I came across them many times, but luckily I escaped.”

Islamabad is a favorable environment for the hogs, whose numbers are estimated to run into the thousands. The capital was founded just over 50 years ago on forested land abutting thicket-covered hills. Today, the city is still crisscrossed with wooded ravines offering cover not only to wild pigs but also to monkeys, jackals and giant fruit bats.

Known to most Pakistanis simply as pigs but to scientists as Eurasian wild boars, the animals are natural residents of Pakistan’s plains and hills. They generally feed on anything from grass and roots to small animals, but Islamabad’s boars appear to prefer trash.

Shahid Hafeez, a lecturer at the University of Agriculture in Faisalabad, found that though the local pigs’ stomachs contained plants, dead animals and some mud, 58 percent of the contents was garbage. Retrieved items included Tetra Pak packaging, plastic bags and diapers.

Islamabad’s pigs have virtually no predator with the exception of the occasional leopard or non-Muslim poacher. Every year, sows give birth to one or two litters of up to eight piglets each. Given the high reproduction rate, experts estimate that a boar population that has shrunk by 90 percent can recover within three years.

Authorities have resorted to mass killings in the past. In Punjab province, to the south of Islamabad, farmers were paid about $1 for each pig they killed provided they mailed the pigs’ tails to the appropriate government office. Up to 20,000 tails were collected annually, but the program was discontinued in the 1980s, apparently for lack of funds. At one point, the Pakistani army was also called to the rescue and slaughtered 10,000 pigs in a single operation.

Dealing with a burgeoning pig population in an urban environment is more difficult. Shooting is not an option, and poisoning has met with limited success.

Islam considers pigs dirty and unfit for human consumption. Manan Khattak, who sells bricks near a wooded gully frequented by pigs, said he is not afraid of them but avoids uttering the word “pig” or even making eye contact with one.

“We don’t look at them intentionally,” he said. “We try to ignore them.”

For many others, potential bodily harm remains the main concern. At more than 200 pounds and equipped with protruding tusks, adult males can be particularly intimidating. “At nighttime when you see them you think it’s a bear,” said Mahmood Chaudhry, a city wildlife management official.

Khan, of the wildlife foundation, said the car of a friend flipped over after hitting a large boar. He said several encounters with wild boars have led to human deaths.

“If they hit you here,” he said pointing to his belly, “you are going to die.”