Karin Lynn, a retired engineer, clamps on protective earmuffs each night to shut out the raucous 3:30 a.m. crowing of roosters while trying to sleep in her bedroom on the 27th floor of the Marco Polo Condominiums in downtown Honolulu.

Chinatown residents are accustomed to roistering merrymakers, but they’ve gotten a nasty shock from a new source of noise pollution — the ear-piercing din made by the male of the jungle fowl species, starting as early as 2 a.m., says Ernest Caravalho, who lives on the 20th floor of Gateway Plaza on Nuuanu Avenue.

Maddened by the persistent racket from an expanding horde moving into the Ala Wai corridor, disturbing their sleep nightly, an impromptu neighborhood posse began forming almost every night in the McCully district last summer to try to chase down and catch the worst of the perpetrators.

There’s a barnyard invasion coming into Honolulu’s urban core, as Hawaii’s colorful jungle fowl increase their unprecedented migration into downtown areas. Long a staple of country life on the island’s rural fringes, feral chickens are moving uptown.

Community groups are speaking out in protest. Complaints are on the rise at neighborhood boards in Manoa, Hawaii Kai, Kahala, McCully/Moiliili and Downtown/Chinatown, said Lloyd Yonenaka, executive secretary to the Honolulu Neighborhood Commission.

“Chickens are coming to the city,” he said. “Neighborhood boards in the country don’t talk about it; they’re used to it.”

An increase in numbers is causing some city residents to consider the intruders as a kind of conquering army. Honolulu has a small pilot program that is aimed at trying to reduce the number of feral chickens, but a state initiative to take stronger action failed in the last legislative session, and some people, exasperated by the scope of the problem, are calling for more militant action.

Solutions involving nets, pellet guns, birth control and drug-laden bread crumbs are all being considered.

“Chickens are wandering around like they own the place,” Lynn said. “They just don’t belong in an urban environment. It seems to be there’s no control over it and it’s getting worse … It’s a feral menace.”

People who choose to live in Chinatown are used to noise, Caravalho said, but this is something different.

“Block parties. Bars getting out. People yelling because they had a great night. I get that. I live in the city. But chickens I don’t expect,” he said.

“We have a problem with feral chickens. Big time.”

What city dwellers in Honolulu have learned is that it’s not a single cock-a-doodle-doo at dawn like in nursery stories but a call and response that can be lengthy, a sort of conversation between birds that allows them to greet each other or issue warnings of danger. It can go on for hours and can occur at all times of day but is most jarring at night in what would otherwise be quiet, peaceful hours.

The number of vocal birds can increase rapidly. Many residents are reporting seeing hens with as many as 10 chicks. Cute as they are when young, each brood contains both males and female chicks, half of which will grow in time into strutting roosters. As adults, they are often beautiful, even regal, but lacking natural predators and no longer utilized as a food source like in olden days, they are growing in numbers with no clear or easy way to stop the proliferation.

Their populations are also increasing because people are feeding them. In McCully, for example, some residents have made it a habit to feed them table scraps, which has the effect of drawing more and more birds to one location on a regular basis. They also try to prevent others from trapping or transporting the birds away, residents say.

Complicating matters is that some people are deeply bothered by the cacophonous cawing and others are less affected. Deep sleepers and those who live in air-conditioned buildings with thick tempered glass don’t hear them as much as people living with open windows.

Tim Streitz, chair of the McCully/Moiliili Neighborhood Board, has been monitoring reports about screeching chickens in his densely populated neighborhood, which is bounded by the Ala Wai Canal to the south and Kalakaua Avenue and Punahou Street on the west and the H-1 freeway on the north.

“They’ve been infiltrating into the urban area,” Streitz said, noting that people in his district were reporting feeling groggy, grouchy and unproductive because of persistent sleep loss due to noisy crowing.

That includes Streitz himself, a government employee who has been living in the same seven-story building on Lime Street for almost a decade.

“We’ve got old-style development with jalousie windows,” he said. “The sound of the roosters just penetrates throughout our buildings.”

But he and others in the McCully area said they couldn’t get elected officials to take the issue seriously, and that they came to believe it was necessary, as he says, to “fend for themselves.”

One night, Streitz joined with other neighbors, people he didn’t know, in a kind of unorchestrated flash mob, desperately trying to catch the noisiest of the chicken population that had taken roost in bushes on their streets.

Janice Shimizu, his neighbor from across the street, happened to spy him positioning himself to trap one, holding a net in one hand and a box in the other. She had long been bothered by a bird she called “the loudest rooster I have ever heard,” and she decided spontaneously to join Streitz in the hunt. Together they began chasing the fleeing birds; others soon joined in.

The birds scattered quickly and it was hard to catch them, Streitz said.

“They are pretty fast and fly up on the power lines or on someone’s roof, where you can’t reach them,” he said. “It was pretty difficult.”

Meeting about four times a week for three months, from May to July, the vigilante brigade ultimately cornered and caught at least five — two roosters, two hens and a chick, using fish nets, boxes, ropes and traps, placing the captured creatures in pet carriers and transporting them to distant locations for release.

One exasperated homeowner eventually caught a rooster with his bare hands, Shimizu noted.

They had no choice, she said, calling their efforts a necessary joint action to preserve the quality of life in their neighborhood.

“If we don’t get rid of this rooster, another one will come and another and another and another,” Shimizu said. “It’s too late then.”

Streitz believes that government needs to play a bigger role. He has circulated a memo with ideas on things the city could do to cull the feral chicken herd. He suggests the city consider loaning traps to residents, with city-funded drop-off spots where the captured birds can be delivered.

He raised the idea of allowing people to shoot them with pellet guns or bows and arrows, as long as they first received safety training. He also suggested that interfering with chicken removal be declared a crime.

The city could also make it illegal to feed feral chickens.

The city recently launched a pilot project, administered by the Department of Customer Services, to fund feral chicken captures in “high complaint” areas, said Honolulu Council Member Calvin Say, whose district includes the McCully area.

The city contracted to pay an initial $25,000 for the first phase of the project to Sandwich Isles Pest Solutions to remove chickens in a handful of zip codes, mostly on city lands, including Ala Wai Park, Smith Beretania Park, Kailua Park and Kamalii minipark. A second phase is budgeted at another $25,000.

City officials said that they have caught 152 feral chickens.

“We can’t do much to address all the feral chickens but the city is doing its best,” Say said.

One neighborhood targeted for remediation is Lime Street in McCully.

Patrick Nunneri, general manager of Sandwich Isle Pest Solutions, appeared at a recent informational meeting held by the neighborhood board, telling people he would pursue problematic fowl onto private property if he had the permission of the property owner. Nunneri said captured animals were exterminated.

Nunneri’s assistance was eagerly sought by several community members.

“How much does it cost to bump off a rooster?” asked McCully board member Paul Robotti.

Nunneri asked him to provide an address, indicating the pilot project would fund the cost.

Say said the city is considering other approaches as well. The city has installed signs in five city parks urging people not to feed feral chickens. It also initiated a public service campaign sharing the same information.

Say also sought a report from the Office of Council Services on the broader issue.

According to the report, the city’s trapping program has raised other concerns, including whether the traps are humane and whether the birds should be relocated or exterminated.

Some cities on the mainland are also dealing with feral chicken problems, city officials said. Key West, Florida and Yuba City and San Juan Bautista, both in California, for example, have made it illegal to feed feral chickens because it caused a population explosion.

In Bermuda, feral chickens are fed bread coated with an anesthetic, allowing them to be caught and euthanized more easily, city officials said.

Say said it would be helpful if the state would work with the county to find solutions to the problem.

State legislation, Senate Bill 2195, would have required the state Department of Agriculture to collaborate with the Department of Land and Natural Resources to establish a pilot program to manage the population of feral chickens. But it failed to pass in April.

Officials at both state departments testified that the issue was better left to local government.

The Hawaiian Humane Society blamed the proliferation of feral chickens on irresponsible behavior by cock fighting organizations, and suggested bird birth control was a better option to reduce the size of flocks.

Dozens of residents testified in support of the bill, not just because of the noise but also because of health and safety concerns. Dozens more testified against the bill, arguing that chickens have as much right to live as humans.