Across L.A., it’s the year of the rat

The real estate boom may have moved rodents out of their homes and into yours.

Developers are turning vacant lots into sites for homes, stores and office buildings. And while a new house down the street will bring some new neighbors, it could also bring unwanted houseguests: rats and mice.

“When bulldozers scrape the soil and level it off for construction, all those animals that made that lot their home have to go somewhere else,” said Todd Veden, a technical specialist for Terminix pest control in Southern California. “If your home and property are attractive to them, they’ll stick around.”

In addition to the displacement caused by developers tearing up their homes, the rodent population in general may be higher than normal because of last year’s heavy rains. The rain created more vegetation, which in turn increased the population of snails and insects -- rat food, said Tawnia Pett, public outreach coordinator for the Orange County Vector Control District.

Business has been so good for exterminators that some of them say they’ve had to turn away customers.

“It’s been the biggest rat year I’ve ever seen,” said John Gloske of First Quality Pest Control in Northridge. “We’ve been swamped with calls. We just can’t get to them all.”

No area is immune from rat and mice infestations.

“They’re truly equal-opportunity pests,” said Dr. Jonathan Fielding, director of the Los Angeles County Department of Public Health. “No matter where you live or what the value of your property is, if there’s a place where they can find shelter and food, they’re surviving, and in some cases, thriving.”

There are two types of rats in Southern California. The larger Norway rat is generally found in urban areas, while the more common roof rat prefers residential neighborhoods.

Rats and mice generally stay hidden in their nests and burrows during the day and search for food at night. A rat scurrying across a power line or trotting along the sidewalk in the middle of the day generally means that the local rodent population is out of balance.

Experts tend to discount the old rule of thumb that one rodent found indicates the presence of 10 or more in the shadows. “It could mean that there are too many in one area and the weak ones are getting forced out to look for new territory,” Pett said. “It could also mean that there’s a large colony in your ivy.”

How can you tell if your property is a potential rat or mouse haven?

Do a careful exterior walk-around to specifically look for areas that could provide shelter, food or water. Start with the ground cover. One of the staples of Southern California landscaping, ivy, is also a dream housing complex for all sorts of rodents because it shelters them from predators, Pett said.

“You don’t have to tear out all of your ivy,” Fielding said. “But certainly you should thin it to cut down on the amount of shelter it provides.”

Overgrown vegetation is a problem, Gloske said. “Huge overhanging bougainvillea might look pretty, but it’s an invitation to all of the rodents in the neighborhood.”

Also make sure wood or debris piles are at least a foot off the ground, and try to keep the yard tidy. Store bagged garbage inside a bin and keep pet food dishes clean. Regularly pick up fallen fruit from trees, and keep the snail and slug population to a minimum by cleaning up lawn clippings and fallen leaves, which provide these garden pests with food and shelter.

Keep pools and spas covered at night or make sure the water level is high enough to keep the filter working, but too low for a rat to lean over and get a sip. Check for hose or sprinkler leaks, which attract thirsty rodents.

Repair holes in screens, siding or other entryways for rats and mice. “Remember, if they can find a spot that’s indoors, away from the elements, they’ll take it,” Gloske said. “They can get in through the tiniest of openings, and if it’s too small and they really want to get inside, they’ll gnaw on the hole to make it bigger.”

This brings to mind the tales of giant rats keeping people awake with their constant grinding to get inside the house. “It may not be that dramatic, but it does happen,” Veden said. “If you’re hearing a gnawing sound at night, it could be that something is trying to make a hole.”

The first sign of an infestation inside is droppings. Rat droppings are about a half-inch long and are pointed at both ends; mouse droppings are similar in shape but significantly smaller.

Other indications are small pathways visible through attic insulation, small hairs and an odor of urine in cabinets.

A real danger is that rodents can bring bacteria into living areas. The fleas from rats were notorious carriers of bubonic plague in centuries past, but the last known case of plague linked to rats in Los Angeles was in the 1920s. More commonly, they can carry bacteria that cause murine typhus as well as the food-borne illnesses salmonellosis and leptospirosis.

A dog or cat could be a good alarm to let you know about an infestation. Their hearing and sense of smell are better than humans’, and they’ll probably be the first to know if there’s a rat or mouse in the house.

“If they’re acting peculiar and they’re trying to get to some corner or cabinet, they may be trying to tell you something,” Gloske said.

Don’t count on a pet to be an exterminator, however. “Cats and dogs are too well-fed to look at rats and mice as anything other than toys,” Pett said. “A cat will bat them around and kill them, but it’s not a serious predator.”

Rats and mice tend to fall prey to coyotes, snakes and even owls, but man remains their No. 1 nemesis. County and city health departments offer advice to homeowners on what they can do to their property to stop rodent infestations, and some provide poison bait that can be used in outdoor traps. The Los Angeles County Public Health Department website, lapublichealth.org/eh/progs/consumer/vectman/pstbltns.htm, has information on topics such as how to make a poison bait station. Most hardware stores sell various types of traps.

“The old-fashioned spring traps have been around for 100 years and they’re still pretty effective,” said Carlos Lemus of B & B Hardware in Culver City, who reported that the number of homeowners looking for rodent-control products at his store has “skyrocketed” over the past year.

Other traps include glue paper and battery-powered traps that electrocute the rodents. Poisons are effective, although these should be used with extreme caution. The bait must be secure in the trap and not accessible to pets or children.

For those who don’t want to take this on as a do-it-yourself project, exterminators will generally charge $75 and up to set traps and bait.

Overall, being aware that rodents are in the neighborhood and that new construction could send them your way is probably the best way to counter them.

“Don’t think that because you’ve never seen one they’re not there,” Veden said. “But keep your property from being an easy home for them, and they’ll go somewhere else.”