Rats
An uptick in urban rats has homeowners frantically trying to figure out ways to thwart infestations. “It is a bad year for rats,” said Dana Sanchez, wildlife specialist for Oregon State University Extension Service.“Eugene and parts of Portland are experiencing a noticeable increase. It could mean there are more rats, or it could be evidence that people are providing more habitat.” Rats and Mice are rodents that not only destroy and damage materials by gnawing, eating and contaminating, but they are also a danger to human health through the transmittal of disease.
Winter is always a busy time for rodent control but this winter could be worse than normal.
Rats — in this case non-native black (Rattusrattus) and brown (Rattusnorvegicus) — are drawn to any sort of outside food sources such as pet food, chicken food, bird seed and kitchen scraps in compost piles. Even compost without kitchen scraps provides insects that rats consume, unless the pile is kept hot enough to kill them. If rats get inside the house, they’ll dine on whatever food they find there and look for places to nest and reproduce.
Both species are very opportunistic and have an easy time adapting to living in the presence of humans.
You can identify the two rats, if you want to, by color and size. Black rats weigh in at 4½ ounces and grow up to 5 to 6 inches long; adult brown rats weigh 9 to 10 ounces and reach up to 16 inches. Many people are afraid of rats, and there are good reasons for that. There are definite social norms that say if you have rodents living near you, it’s associated with dirtiness, garbage and waste products. There’s a reticence to admitting to seeing rats or talking about them because there’s a fear of public shaming. That works to the rats’ advantage because people aren’t finding cooperative solutions to a collective problem.
Signs of Infestation Include:
- Gnaw Marks: New gnaw marks or holes tend to be rough where older marks are smooth from wear. Older markings are often greasy.
- Droppings: Fresh droppings are soft and moist whereas old droppings are dried and hard.
- Tracks and Footprints: Front foot 4-toed usually in front of a longer hind print with 5 toes. Fresh track are clear and sharp whereas old are partially obscured by dust.
- Rub Marks: Dark greasy markings of vertical surfaces. Fresh marks are soft, greasy and easily smear whereas old are dry and flaky.
- Burrows: Found in earthen banks, under concrete slabs and under walls. If active free of dust and cobwebs. Main opening usually with hard packed soil, rub marks may be visible.
- Runways: Consistently follow same paths, usually along walls, stacked merchandise, etc. Active runways will have a greasy appearance, free of dust, cobwebs and will contain fresh tracks and droppings.
- Damaged Goods: Meat, fish, cereal, fruits and vegetables. Dog food is a favorite.
Control
The key to control is identification, sanitation, harborage elimination and rat-proofing. While outdoor food sources contribute to a rat problem, unkempt yards with woodpiles or old furniture lying around provide rats with nesting sites. And point of access inside and outside the home, such as gaps around doors and windows or in kitchen cabinets and behind stoves, can also invite them in, so a feeding ban won’t be a comprehensive fix.
Mice
Mice can live in many types of habitats, including man-made structures. Mouse infestations can be more common in homes than rat infestations. Since they are mostly active at night, mice may be difficult to see. Signs of chewing, nesting or droppings can help identify a mouse problem. Although they only live for 1-1 ½ years, mice reproduce quickly. Prevention and early detection can keep damage from getting out of control.
Prevention
- Reduce clutter inside and out. Clutter may allow mouse activity to go unnoticed.
- Check unused cars for evidence of mice. Mice can damage wires and other parts.
- Mice are excellent climbers. Trim or remove dense vegetation, including tree limbs, near gardens or buildings.
- Exclude mice by sealing cracks and crevices larger than a quarter inch.
- Install door sweeps and weather stripping to keep mice from crawling under doors.
- Remove materials mice may use for nesting or shelter, including cardboard boxes and newspapers.
Control
- Identify your rodent first. Mice may look similar to young rats but certain features can tell them apart. Try contacting your local Cooperative Extension Service.
- Unlike rats, mice may not need a source of water if their food is moist enough.
- Check for mouse nests near evidence of chewing. Mice usually stay within 30 feet of their nests.
- Mice create brown or gray smudges on walls and other surfaces where they travel. These marks can identify heavily used paths or entrances.
- Mice have teeth made for gnawing. Store unrefrigerated food, pet food, and birdseed in jars, tin boxes, or durable plastic. Large infestations may require a combination of methods, including the use of traps or rodenticides.
- Use small amounts of bait at many trap stations. Use a variety of food types to find what bait works best.
- Consider hiring a professional. There’s an art to managing mice.
- If you choose to use a rodenticide bait, always read and follow label directions.
