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).

Rodent Solutions

Steps to Rodent Control

Roof rat survival depends upon the existence of 3 basic environmental factors: (1) Food, (2) Water, and (3) Harborage.

STEP 1: Eliminate Food and Water

  • Remove all potential sources of food from the premises, such as bird seed left out for birds. Routinely harvest ripe fruit and pick up all fruit that has fallen to the ground.
  • Store pet food in metal containers with tight sealing lids and do not leave uneaten pet food outdoors.
  • Avoid storing food in garages and storage sheds unless it is in rat-proof covered metal containers.
  • Control snails and clean up pet feces because they are favored food items.
  • Keep trash cans closed at all time with tightly fitted lids.
  • Repair leaking eliminate any other faucets, sprinklers, or other piping. Keep drain covers tightly fastened and  unnecessary standing water.

snap trapSTEP 2: Destroy Rats

  • Rats should be snap trapped if they are inside a residence or building. Place traps near nesting areas or where rats are likely to hide. Do not place traps where children or pets will disturb or be harmed by them. Remember, snap traps are very DANGEROUS!
  • Poisoning with baits indoors is NOT recommended because a rat may die inside the structure and create an odor and fly problem. Poison baits may be used when following recommended guidelines.
  • Remove dead rats by placing animals in tightly sealed containers for proper disposal. Clean and disinfect the affected areas.

STEP 3: Eliminate Shelter & Harborage

  • Close all openings larger than ¼ inch to exclude rats and mice.
  • Repair or replace damaged vent screens.
  • Remove all trash and debris.
  • Stack woodpiles, lumber and household items at least 18 inches above the ground, and 12 inches away from fences and walls.
  • Trim trees, bushes and vines at least 4 feet away from the roof.
  • Remove heavy vegetation away from buildings and fences.
  • Thin vegetation to allow daylight in and remove rat hiding places.

STEP 4: Maintain a Rat Free Property

  • After rats have been reduced, prevent re-infestation by keeping harborage and food sources to a minimum.


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.

Rodents & Vegetation

rat in holeMany plants species harbor roof rats. Whenever possible, these plants should be replaced with species which achieve the desirable effects of ground cover, but will not contribute to the rat population. Characteristics to look for in a desirable ground cover are:

  • Plants should be low growing, not more than 10 inches in height.
  • They should not be climbers.
  • Fruiting plants should not be used.
  • Plants should provide soil stabilization.
  • Plants should require a minimum amount of water once established.
  • Once established, plants should be properly maintained.