This document contains information about the biology and management of the House mouse. A wide range of management options is listed. From this list, the IPM Practitioner can choose options to develop a unique management plan for each particular customer site.
Management Objectives for the Pest at the Particular Site
What do you want/need to accomplish at the site in regard to the pest flies?
The answer to this question will vary, depending on the site and the customer. Some examples are:
- Reduce mouse complaints in the building and work with occupants to prevent future complaints.
- Work with the building manager or homeowner to prevent future mouse infestations.
- Help client comply with Health Department regulations.
House Mouse Identification
- The house mouse has a small, slender body reaching between 5 and 8 inches in length and weighing about a ½ ounce.
- They have a buff or light brown upper body that fades into a grey underside.
- The tail is naked, scaly and longer than the head and body
- The body itself is scantily haired with large ears and pointed nose, which distinguishes it from a young Norway rat which has small ears, and a blunt nose.
Why the House Mouse is Considered a Pest
- Mice contaminate food and eating utensils.
- Mice can cause severe damage to structures from gnawing. They can cause fires, explosions, indoor flooding and damage to computer systems as a result of their gnawing on utility pipes and electrical wiring.
- Mice can carry a number of diseases. Hantavirus, a potentially lethal disease, is primarily carried and transmitted by the white-footed deer mouse.
Conditions California Health and Safety Code Sections that relate to mice and cleanliness in food establishments:
114010. “All food shall be prepared, stored, displayed, dispensed, placed, transported, sold, and served as to be protected from dirt, vermin, unnecessary handling, droplet contamination, overhead leakage, or other contamination.”
114030. “A food facility shall at all times be so constructed, equipped, maintained, and operated as to prevent the entrance and harborage of animals, birds, and vermin, including, but not limited to, rodents and insects.”
114040. “The premises of each food facility shall be kept clean and free of litter, rubbish, and vermin.”
114050. “All food facilities and all equipment, utensils, and facilities shall be kept clean, fully operative, and in good repair.”
Biology and Behavior of the House Mouse
To be successful, management strategies must take into consideration the biology and behavior of the pest. Understanding the biology of a pest can reveal weaknesses and vulnerabilities that can be exploited when trying to manage the pest.
- The House mouse originated from the plains of central Asia and was transported on trade ships.
- With the exception of humans it is the most numerous and widespread mammal on Earth.
- Mice become sexually mature between 5 and 8 weeks old and have a sexual cycle of 4 days.
- House mice can breed year long. Outdoors mice are seasonal breeders, with peaks in spring and fall.
- A female produces between 4 and 7 pups per litter after a gestation period of about 20 days. The pups are born blind and naked but within 7 to 10 days they are covered with fur and their eyes and ears are open.
- Weaning takes place around 21 days.
- The average litter size for the House mouse is between 6 and 7 with up to 10 litters per year (depending on food availability). If conditions are right one female mouse can give birth to a litter every 24 to 28 days.
- A female House mouse will stop producing young after about 15 months, but she can live much longer.
- The lifespan of an average House mouse is 1 to 2 years. The maximum lifespan is 6 years.
- The House mouse is very curious and will intensively investigate new objects or surroundings. They are constantly exploring new things near the nest and actively forage for food in a 10 ft. radius from the nest.
- Typically nocturnal animals, the House mouse will be most active after dusk and again right before sunrise. Indoors, mice may have period of active foraging during the day but will primarily forage about 30-60 minutes after human activity has ceased.
- The House mouse is typically omnivorous and opportunistic in its feeding. In the wild mice will forage on many types of plant seeds, but also snails, slugs and other insects. In and around buildings they will consume almost any readily available food but prefer cereals and grains.
- When water is abundant, the House mouse will consume 1 to 2 ounces per day. However, the House mouse is very adapted to going long periods with very little water, obtaining its water requirements from its food sources.
Most established mouse populations inside buildings exist in groups of related individuals within which there is a high degree of social contact.
These populations are territorial and defended by a single male.
Like rats, mice will typically not cross open spaces with little or no cover and prefer to travel instead along walls and corridors with some cover.
Factors that Favor the House Mouse
- Poor sanitation provides rats with ample quantities of food to sustain large numbers of mice.
- Improperly stored food and waste allows another food resource for mice populations to flourish on.
- Clutter and improper storage practices provide abundant hiding places, nesting sites, and travel routes for mice.
- Dense vegetation and ground cover can act as excellent nests and rodent highways.
Monitoring and Record Keeping
The purpose of monitoring is to track pest activity in order to catch small problems before they become overwhelming. Monitoring also makes it possible to properly time pest management actions and to evaluate the effectiveness of those actions. Records are kept to document the methods and products used and to record information that can be used to fine-tune pest management methods and plan future actions.
Visual inspection coupled with snap or glue traps are the most effective means of monitoring for the House mouse.
The “tolerance level” is the number of House mice that triggers action to control the pest. The tolerance level is site-specific and differs depending on the customer, the location, and other factors. Determining the tolerance levels for a site helps prioritize work that must be done to control the pest.
Management Strategies for Mice
Pests need food, water and shelter to survive. Pests also need access to a structure and a way to move around within the structure in order to make them a nuisance inside a building. If even just one of these factors can be reduced (or eliminated), the environment will support lower pests and pests will be less likely to invade our living spaces.
To limit availability of food and water
- Store food properly: in the refrigerator, in metal, glass, or heavy plastic containers with tight fitting lids.
- Do not leave food out overnight.
- Store bags of pet food, birdseed, and grass seed in rodent-proof containers, or at the very least, inspect them often for any signs of gnawing.
- Pick up fallen fruit and nuts from trees daily.
- Limit areas for eating and storing food and enforce these rules. The fewer designated areas, the easier it will be to limit pests.
- Fix leaky plumbing and eliminate any unnecessary standing water.
- Dispose of all garbage in dumpsters or garbage cans with tight fitting lids that are kept closed.
- Remove all garbage from the building at the end of the day
- Wash all garbage cans that contact food wastes with soap and water at least every 2 weeks.
- Require your refuse company to clean the dumpster or replace it with a clean one frequently.
- Never store extra garbage outside the dumpster or garbage cans, even if it is in cardboard boxes or plastic bags.
To limit availability of shelter/harborage
- Seal all openings in a structure that would allow access to the structure.
- Reduce clutter and debris by using proper storage techniques.
- Remove rock and woodpiles and construction debris.
- Trim trees, vines, bushes, grass, and weeds at least 2 feet from all buildings to decrease cover for rodent runways, to prevent hidden access to buildings and to make inspections easier.
- Trim tree and shrub branches 3 to 6 feet away from the building.
- Eliminate dense plantings or break them up with pathways, stretches of lawn, or very low groundcover.
- Avoid large expanses of low groundcover that could allow mice to run for long distances without being seen.
Physical controls employ physical means to remove mice or prevent their access to or movement within a structure.
To prevent mouse entry:
- Trim trees and bushes at least 2 feet from the structure.
- Make general building repairs and seal large and small holes in structures both inside and out. Seal small holes with steel or copper wool and caulk.
- Seal vents with ¼ inch hardware cloth.
- Seal gaps where pipes and wiring enter the structure.
- Weather-strip doors and windows, use metal kick plates or raised metal doorsills to prevent rodent entry.
- Make sure air conditioning units are well sealed, especially those on the roof.
- Repair broken sewer pipes.
- Install threaded caps on drains.
- Use snap traps or glue boards and record their location on your site plan.
- Move objects around to funnel mice into traps.
- Monitor traps regularly and frequently, and keep bait fresh.
In general, chemical controls should be used as a last resort or in emergency situations. Rodenticides can pose hazards to children and pets. Poisoned rodents may also die in inaccessible places and cause odor and fly problems. Overuse of many rodenticides may also lead to widespread resistance. Exclusion methods are heavily preferred over any chemical means.
The IPM Partnership
The PCO-Customer Partnership is Very Important
IPM works best when the customer and Pestec form a partnership to tackle the pest problem. The House mouse cannot be managed satisfactorily without the cooperation of the customer, especially in the area of sanitation. Pestec will discuss the findings of the initial inspection and any subsequent monitoring sessions with the customer to determine which issues and tasks will be the responsibility of Pestec and which will be the responsibility of the customer.
Information is a powerful tool in IPM. Information can help change people’s behavior, particularly in how they store food and dispose waste. Changing these behaviors is often an invaluable part of managing ants. Building occupants and homeowners can also help in the early detection of pests so that Pestec can be alerted before the problem is severe.
Pestec’s highly trained and knowledgeable staff can provide pest management education or training sessions for facilities managers, risk managers, building occupants, homeowner associations, and others.