Rodent Signs

Signs of Rodent Activity

• Damaged, partially eaten fruits and nuts, such as walnuts, oranges, and avocados.
• Broken snail shells under bushes, on fences or near nesting sites.
• Signs of gnawing on plastic wood or rubber materials.
• Greasy rub marks caused by the rat’s oily fur coming in repeated contact with painted surfaces or wooden beams.
• Rodent droppings are usually signs of significant rodent activity. The droppings are randomly scattered and will normally be found close to a rat runway, feeding location, or near shelter. Droppings can be found in forced air heaters, swimming pool heater covers, and water heater closets.
• Sounds (gnawing, etc.) from attic, subfloor areas and wall spaces.
• Visual Sightings on utility cables, tops of fences, or in trees.
• Burrows in the ground, and adjacent to sewer lines are signs of Norway rat. activity.

Common Rodent Entry Locations

• Broken or missing foundation vent screens or attic vent screens.
• Overlapping roof.
• Open wooden meter boxes (in older homes).
• Space between roof jack and vent pipe.
• Under or on sides of garage door.
• Brick chimneys which have settled away from house.
• Crawl hole with poorly fitted lid.
• Tile roof.
• Broken or open building sewers which connect to the main sanitary sewer. (Norway rats).
• Toilets. (Norway rats).

Building Maintenance

Roof rats can enter even small exterior opening of a home. Important steps a homeowner can take are inspecting and repairing:

• Basement windows and ventilation ports.
• Attic vents and louvers.
• Gaps between roof and chimney.
• Tile roofs along the eaves
• Vent pipes and shafts.

All openings such as these should be screened with ¼ inch galvanized hardware cloth and inspected at least twice a year. Gaps around pipes and electrical conduit should be sealed and cracks around doors and windows should be sealed, and cracks around doors and windows should be weatherproofed. Tree limbs should be kept well away from the roof and walls of the house.

Rodent-proof Your Building to Prevent Rodent Entry

• Close all openings larger than ¼ inch to exclude rats and mice.
• Repair or replace damaged vent screens.
• Screen vents, holes and overlapping roof with 16 or 20 gauge ¼ inch hardware cloth.
• Use sheet metal collars around pipe entrance on wooden walls.
• Use cement fill around pipe in brick, stone or stucco walls.
• Subfloor crawlspace entry hole must be sealed with a door or a lid that will excel finger size objects.
• Removable lids should fit so that the lids must be lifted up to open.
• Use sheet metal edging along door bottoms to prevent entry and gnawing by rats.
• Repair broken or open building sewers to prevent sewer rats infesting property from broken or open sewers which connect to the main sanitary sewer where they may live.