Have you heard noises in your attic?
Rats can squeeze through openings the size of a quarter, and reach sexual maturity in just 5 weeks. According to the Center for Disease Control, rodent droppings and urine can contribute to and cause allergies, asthma, bacterial diseases, not to mention the mites and fleas that often come along for the ride. Additionally, they may be sources of swine dysentery, brucellosis, sarcoptic mange, and tuberculosis, all of which affect livestock or pets.
Rats and mice also cause serious damage to insulation, electrical wiring, plumbing, and other structural components of buildings. Insulation damage and the resulting energy loss may amount to a loss of several thousand dollars in only a few years. Fires from damaged electrical wiring or nests in electrical panels destroy property and threaten human safety. Rodent damage has been documented in homes, apartments, hotels, office complexes, retail businesses, manufacturing facilities, food processing and warehouse facilities, public utility operations (especially power and electronic media operations), farm and feed storage buildings… really, just about everywhere!
Common Entry Points in Residential Buildings
- Utility entry points include underground electrical and communication trunk lines, and exhaust vents for clothes dryers.
- Power lines and tree branches can provide access to the roof, where improperly installed flashing, loose shingles, or loose mortar in chimneys can provide access to your attic.
- Sewage systems
- Poorly fitted doors and windows
- Gaps or flaws in foundations and slabs, or where the wall framing meets the foundation or slab floor
Signs of Rodents
When it comes to rodent control, you must pay attention to the details. Sometimes the signs of a rodent invasion will be obvious, but most often not.
- Rodent Hair – usually thin and light in color, can be found along the trails that rodents travel and stuck in the edges of holes.
- Sebum Trails – the grease from a rodent’s body. Can often be found even if the hair has been swept away.
- Rodent Droppings – the most obvious sign. Take note of the location, age and size to help determine the best plan of attack.
Each pest situation is unique. Dr. Bobby Corrigan, who holds a PhD in Rodent Control from Perdue University, stated in a recent conference, “The goal of rodent control is not extermination, but to efficiently manage and, where possible, eliminate local rodent populations in an environmentally responsible fashion.”
Part of that lies in an understanding or rodent behavior, including habitat preferences, navigational abilities, feeding habits and social stimuli that encourage rodents to choose one location over another. Like a mouse can learn to navigate a maze, rats can memorize pathways that lead to food or shelter, sometimes ranging up to 450 feet away from their nest. They use pheromones to mark these pathways.
Rodent Behavior and Preferences
Thousands of years ago, the Norway rat (the most common rat, also known as the brown rat) lived in northern China. At some point, it threw in its lot with humans, invading homes and farms and living off scraps. They snuck aboard boats and came to Europe, and eventually America. How they behaved before is not as well know, but we do know the preferences of the modern commensal rat:
- Lines – rodents are hard wired to travel along lines. Think the edges of walls, along pipes, beams and ducts
- Warm Areas – warmth is critical for mice because their bodies lose heat rapidly, but rats prefer warm areas as well.
- Shadows – rodents will seek out shadowy areas to use as pathways
- Corners – corners make rodents feel safer, so this is where nest are most likely to be
- Voids – rodents will gravitate towards voids in structures and equipment because they perceive them to be ready-made nesting areas
- Quiet Zones – Like the back of a storage area, are very attractive to rodents.
Using poison baits and traps is a band-aid solution. Exclusion, also called rodent proofing, is the best rodent control technique. If they can’t get inside, they can’t be a problem, right?
Exclusion should never be considered a permanent solution. Even the best exclusion can be overcome by determined gnawing over time. Continuing, ongoing inspection, exclusion, sanitation and monitoring are required to keep buildings tight enough to prevent or control re-infestations and deprive rodents for food and shelter.