Island’s rat population is indeed on the rise
Block Island has been feeling ratty lately. There are anecdotal tales of rats gnawing through front doors and garage doors to get at pet food, and a YouTube video shows a rat climbing up a man’s leg while he videotapes waves and flooding during Hurricane Sandy. Rats are being seen in fields and on the streets, and it feels like there are more of them around than in years past.
Turns out, the rodent rumors are right. Rats are among us in greater numbers, thanks to last winter’s unseasonably mild temperatures that provided access to food for the critters. A lack of killing cold also allowed the local population to expand.
At Island Hardware, owner Petie Hunter says sales of rat mitigation devices, be they traps, bait or other deterrents, have increased, and Griggs and Brown wildlife specialist Dennis Chamberlin says rat related calls for help have doubled this year.
Block Island’s Norway rats have been on the island since the arrival of the first ships here centuries ago. They have no predators except for humans and the island’s hawk and owl population.
Winter is normally the great leveler for rats, which live for about a year. A hard winter will kill off the weaker ones. This year, however, Chamberlin says he is seeing a lot of very healthy rats. A hard winter would help, he says, to make a dent in the population.
To help educate others and myself about how to rid a property of rats, I asked Chamberlin to visit our home and offer advice.
Our house is four and a half miles from town and, yes, we have recently seen a rat in the front yard, for the first time in 18 years. There are several marshes and two small ponds on a neighboring site, and a wildlife refuge nearby.
Chamberlin begins his inspection in the basement. Rats, he explains, have a musty odor that he can detect. He picks up no such smell, but still he shines his flashlight over and around our bulkhead door seeking entry points. My education has begun.
A rat, he tells me, can squeeze through a space the size of a quarter. In the basement we find a few spots where this could happen. Clogging those holes with a combination of steel wool and foam, he says, will bar entry. In his estimation, a rat’s tooth is somewhere just below a diamond in hardness. In his work he has seen them chew through cement and all types of woods. Steel wool, he finds is the best solution, because it is one material rats just don’t find palatable.
He beams his flashlight along the walls of the basement. Rats have an oily fur and will often leave smear marks on walls they pass by. They have poor eyesight and must rely on their whiskers and acute sense of smell to find their way. Rats follow paths known as runways close to walls or barriers. They tend to keep to the same routes unless they sense danger.
In winter, as temperatures drop, they must seek warmer shelter, which is why Chamberlin is giving my basement such a thorough inspection. He looks behind and in an old refrigerator and defunct washing machine — possible nesting sites, he explains.
We have some traps and bait set out in the basement. The first is not aligned correctly. With his toe, he moves the trap so that it is against the wall, along the path that a rat might travel. He finds the open container of bait in another corner and explains that the product has lately been outlawed and will soon no longer be sold in stores.
“This,” he says, holding the box up to show me, “is more toxic than any product I use, and dangerous for kids and pets.”
Besides food, rats need a source of water. Indoor sources include a wet basement, or condensation on or around water pipes. In the house itself, rats have been known to drink from toilets and sinks as well as pet bowls.
Chamberlin, who has a pet rat at home, is often amazed at the animal’s intelligence. He has built mazes for it, watched it steal stuff from him and is amazed at the animal’s stealth.
“A rat can go through a site and not leave any evidence,” he says, adding that a mouse would. This gives me pause. Have we covered every possible point of entry?
We decide to stuff possible entry points, such as where oil, gas and water pipes pass through the foundation, with steel wool, as he suggests.
The cellar’s bulkhead is possibly a problem. The inside door is barely functional. But what about the bulkhead itself? We head outside.
Our wooden bulkhead is well built and well sealed, Chamberlin finds. The newer prefab ones, he says, have an opening in the middle where the doors meet and provide easy access to a basement for a rat. He suggests that owners with these kinds of doors stuff one end of the opening with steel wool.
Rats to the outdoor shower
On his knees, he crawls beneath the back deck to search for holes. Still, we are in luck. None are found. Then he pauses near the outdoor shower and shows me two holes. Rats love outdoor showers, he says, because of ready access to water. He finds another entry point near a low deck and possibly another one by the garage. Around the wider property we look for bolt holes where a rat could hide or escape while trying to get into the house or away from a predator. Chamberlin points to some “harborage” sites. Near the garage is a stack of wood he suggests we move. It’s a perfect hiding spot for a rat stealthily seeking entry.
Rats like hiding in plain sight, he tells me. They are generally most active in the early morning and at dusk, unless there is a large colony. Then they will be out foraging for food during the day.
In the backyard, Chamberlin points to the empty bird feeder. Feeders attract rats, he says. (At Island Hardware, Hunter suggests waiting a week or so in between filling a feeder, so that the birds will forage on the ground for the spillover.) Chamberlin also points to dog feces on the lawn. Rats will eat dog feces because it contains undigested particles of food.
What about deer feces? The specialist is not sure, so I call Tom Husband, a professor of wildlife ecology for the University of Rhode Island. He thinks rats probably don’t eat it. What deer eat in the first place, high cellulose plant material, most likely does not have enough nutritional value for a rat. Still, Husband says, critters have proven him wrong. Just recently while doing some fieldwork he watched a Norway rat sitting up on its hind legs and eating a seedpod off of a plant. He had never witnessed that before.
“Nature can make a liar out of you,” he jokes.
I decide to consider a small three-month abatement program. Since we have a dog who might eat rat bait, Chamberlin suggests first trying some placed in the holes around the shower. We will follow this routine for a few weeks and see what transpires. If no dead rats are found, then he will try tracking powder, a substance that is sprinkled at the entry point of the hole. The rat picks it up on its oily fur and then grooms and ingests it. Good-bye rat; but we’ll have to keep a close eye on the dog.
He tells me to store any fertilizer or lawn seed in sealed containers and preferably not in the garage. Outdoor porch cushions or any other materials that could be used as nesting material should also not be kept in a garage.
Don’t just throw rat poison outside
Maura Cousins of Block Island Pest Services finds bait blocks are the most effective for getting rid of unwanted rodents, but emphasizes the blocks must be put out in tamper proof boxes to keep the highly toxic bait away from kids, pets and other wildlife. She warns people not to throw bait out into the wild where animals and children can find it and eat it.
She also suggests that people who leave their home for the winter take pet food with them. The food, she says, attracts rats, which will seek entry points into a home if they smell it.
Cousins agrees with Chamberlin regarding the increase in numbers of rats. She estimates a 25 percent increase in numbers this year. Many of her customers, she notes, are seeing rats in the streets and in fields — not so much in their homes. And she cautions to use spring traps only inside. Outside, they can attract a pet or a child and cause injury.
Island Hardware supplies bait, traps and sonar devices for catching or discouraging a rat’s presence. The store will be phasing out products that contain a substance the EPA has found to be highly toxic (see sidebar). The newer baits come in a heavy plastic housing, an added deterrent for dogs and kids.
In the meantime, Chamberlin suggests islanders take the increase in the rat population seriously. He educates me a little on a rat’s daily routine and life cycle. A rat is persistent and will visit 10 sites a day in its search for food. It does not hibernate, and when winter bears down, it will seek a warm shelter. Foundations of buildings and barrier walls provide perfect nesting spots, cool in summer and warm in winter. They can gnaw a hole two inches in diameter if they want to get into a site. Block Island, he says, is in some respects rat heaven because of the abundance of walls, foundations, shrubs and marsh areas.
Rats prefer to live in colonies, he adds, so if you see one, chances are there are more. In its one year of life, a rat will grow to be six to eight inches long and weigh up to a pound. A female will have four to seven litters a year with six to eight babies per litter.
And regarding those birds at the feeder, “count the birds,” he says, and “understand you attract the same number of rodents as birds to a feeder.”
Cousins suggests simply not having bird feeders.
As for the rats? At the moment, Chamberlin explains. “They are just not getting stressed out.”
Block Island Exterminator Services:
Dennis Chamberlin, Griggs and Brown Pest Control: 1-800-924-8886
Maura Cousins, Block Island Pest Services: 466-7911
New EPA rulings regarding rodenticides
- All rodenticide bait products must now be sold in or with a bait station
- Package sizes are limited to one pound of bait or less.
- Loose baits, such as pellets are prohibited (unless sold in an Agricultural Store)
- No second generation anticoagulants actives may be used (brodifiacoum, difethialone, etc.)