Island beaches may look deserted by this time of year, the streets empty after midnight. But T.J. Hegarty knows better.

For the county's new rodent control officer, this is rat and mouse season, the time of year when rodents are busy searching for winter lodging.

An increased number of rat sightings in the last year prompted selectmen to demand the revival of the county rodent control program, dormant since 1998. In its first three months, the county rodent office fielded 250 calls and made 185 site visits to Island homes and businesses.

But now, Mr. Hegarty plans to target public beaches, prime real estate for rats drawn to the convenient shelter of rocks and easy access to food - trash, fish, bait, nesting piping plovers and bittersweet.

"Beaches have a history of rodent activity," he said. "And the bittersweet, it's like fresh yellowfin tuna to them. They love it."

Environmental police Sgt. Bill Searle said the beaches are like a smorgasbord for rats. "Everything that washes up out of the ocean they eat," he said. "There's more food along the shoreline than deep in the woods."

So far, beaches at the top of Mr. Hegarty's list include Eastville Beach, Joseph Sylvia State Beach and Norton Point. Eastville specifically made the cut after "a group of rats came out to join a mother and her kids picnicking right at the base of the bridge."

The new rat man clearly likes a good rat story, but he'd much rather talk strategy. The rat he's trying to outsmart is the Norway rat. And Mr. Hegarty carries a bag of tricks he calls integrated pest management - glue boards, bait boxes, traps and some plain common sense.

As for the beaches, the tool of choice looks like a large shoe box, appropriately colored black to fit its morbid intent. It's really a tamper-proof bait station, made of plastic and measuring 12 by 12 by 4 inches. The meal inside is poison, an anticoagulant that will take some time to fell the rodent. Unlike the Roach Motel, rats are supposed to exit this box.

"They wine and dine themselves at the location, and if they're big enough, they'll take some back for the kids in the burrow," said Mr. Hegarty.

How many rats has Mr. Hegarty bagged since June? He's not keeping close tabs, but when possible he stores dead rodents in a freezer so they can be picked up and tested by scientists investigating Island tularemia outbreaks of the last two summers.

No other place in the country has experienced even a single outbreak of pneumonic tularemia. The Island's first outbreak was in 1978. Of the 19 cases confirmed in the last two years, 14 were the pneumonic form. One case was fatal.

Harvard University parasitologist Sam Telford has already tested eight rats collected by Mr. Hegarty. None were positive, but other rats trapped on the Vineyard by scientists from the federal Centers for Disease Control have tested positive for tularemia.

Mr. Telford believes that rats, not rabbits, may play a pivotal role in solving the tularemia mystery. Since rats can survive tularemia while rabbits die from it, they may be what Mr. Telford called "inter-epidemic reservoirs," carrying the disease from one year to the next. Dog ticks help pass the disease to other animals and even humans.

But tularemia isn't the only strike against rats. Hosting anything from Lyme Disease to Rocky Mountain Spotted Fever, "their ability to carry diseases is well-documented," said Sergeant Searle.

Experts like Mr. Searle and Mr. Telford said the increase in rat sightings can be blamed on the closing of Island landfills. It's a simple matter of habitat. With the dumps now capped, rats are finding their way to people's homes and businesses in search of food and cover.

With the onset of winter, Mr. Hegarty expects to get more calls. While the rodent control office is funded by the county at an annual cost of $48,000, the service is not free.

Residents pay $40 for an initial visit and $20 for each follow-up. The cost for businesses is $100 with a $40 fee assessed for each subsequent trip.

Mr. Hegarty's approach is not to slash-and-burn, but to understand how the animals are getting into a house. Installing screens over heating vents may be a better solution than laying traps or putting out poison.

"I go to a site and the first thing I do is listen to the homeowner," he said. "The key is not being freaked out but to have respect for them and their intelligence."

No doubt, rats are sturdy creatures and even smart enough to drag traps out of the way without triggering the spring, according to Mr. Hegarty.

"They're marvelous animals as far as being able to survive," said Sergeant Searle.

But neither man is ready to bow down to the rat.

"There's too many of them," said the sergeant. "I don't think the Island has reached its carrying capacity, but we've reached the cultural capacity of rats and skunks. They're more than just a nuisance."

The county started controlling rodents back in 1944. Arnold Fisher was the county rat man for 21 years until he stepped down in 1992. Another officer was hired between 1996 and 1998, but in the years in between, the program has faltered. In essence, rodent control officers have been the rats' only predator on the Island.

"When the program was defunct, it got us off balance," said Mr. Hegarty. "We need the program to maintain the balance. Until the coyotes come, we need it."