Tails of the city

The plump little beasts enjoy gorging on garbage, which helps keep their teeth from growing 4 inches a year. But too much can frustrate their efforts to squeeze through quarter-sized holes or to scale sewage pipes and slink out of toilets.

They also have a tendency to outsmart predators such as Chuck Trainito, who has been patrolling the streets in recent weeks with weapons of rodent destruction.

The inimitable Norway rat - a footlong rodent with small ears, sharp claws, and a long tail - has become an increasingly familiar presence in Boston in recent years, from the alleys of the Back Bay to the basements of Dorchester. In fiscal 2007, city residents lodged 1,675 complaints about rats, 38 percent more than the year before and 23 percent above fiscal 2005, according to the city's Inspectional Services Department.

In the Back Bay, Beacon Hill, and Allston-Brighton, complaints about rats have doubled over the past fiscal year.

Earlier this month, a report issued by a national rodent-control company rated Boston as the third most likely city in the country to confront a surge in the rat population over the next few months, as the creatures begin their breeding season.

The city is prepping for battle.

"Our job is to find and eliminate as many as we can," Trainito said while on a rat patrol this week with a truck full of poison. "They serve no good purpose."

Last month, 16 city health inspectors began poking through the trash, yards, and alleys of some of the most vulnerable neighborhoods - those with lots of trash buildup, high population density, old sewer systems, and proximity to water - in search of traces of the rodents' presence.

As the morning sky threatened to unleash a storm, Trainito and his colleagues used broomsticks to check holes in the dirt, uncovered pipes, and plastic sacks of trash left on the pavement.

"They're smart, but we're smarter," Trainito said.

Then he walked to his truck and showed off the city's armament:

There are the smoke bombs, effective in pipes and sewers, which release a cloud of sulfur and choke the rats.

There are the wax-coated blocks of poison, lowered into catch basins, where they slowly kill. "Over 48 to 72 hours, it clots their blood, and then they suffocate," he said.

There are also the little bags of bait and tracking powder, which work in much the same way as the wax blocks. The most efficient weapons are the Victor Snap Traps, especially when baited with a slice of pepperoni, which Norway rats can smell up to 30 feet away.

"Death comes instantly," Trainito said.

Asked whether he thought such devices were cruel, he smirked, shook his head, and repeated: "They don't serve any positive purpose. The fewer, the better."

As the men walked around Alley 414 near Massachusetts Avenue in the Back Bay, they pointed to the brown, capsule-shaped droppings marking the recent presence of rats. They also pointed out hallmark problems: lids hanging off trash cans, open bags of trash, broken pavement providing warm places for rats to burrow, holes in walls, and scavengers who rifle through the trash.

"Eliminating the food source makes our job a lot easier," said John Meaney, the city's principal health inspector, adding that he hears complaints of rats climbing into homes through toilets about every six months.

"Our biggest concern is for most people their least concern," Meaney said. "We need to educate people and confront their complete laziness."

The New Jersey-based company d-CON released a report this month ranking Boston third of the nation's 32 cities most likely to be infested by rats.

Behind New York and Houston, Boston ranked high on the list because of its age, density, number of restaurants, and proximity to the Charles River and the harbor, among other things, said Dale Kaukeinen, a pest-control consultant and one of the report's authors.

He said the warmer winters the city has experienced in recent years - and probably will see more often as a result of global warming - may account for the jump in rat complaints and any increase in breeding of rats, which live about a year on average and spawn litters of between six and 12 pups, up to seven times a year.

"There's only so much an old, large city can do," Kaukeinen said. "It's like putting out fires."

In Boston, the ranks of rat fighters include men such as Brian Nguyen, who for much of the past 19 years has avoided telling people what he does for a living.

"This isn't something you advertise," he said.

As he passed out pest-management brochures and looked for signs of rats in the gardens of the high-priced townhouses on Marlborough Street, Nguyen said he has become used to the work.

"At first, I was scared of them," he said, pointing out how they eat through metal and dine on everything from rose petals to feces. "Now, it's normal. I deal with them every day."

When the traps do their job, Nguyen said, it's a good day.

He slides on his gloves and goes to work.

"I pick them up by the tail, wrap them in a bag, tie it, and then put it in the trash," he said. "No problem."

David Abel can be reached at dabel@globe.com.