Mouse Biology

Some facts about mice

  • Adult mice typically weigh 10-30 g and have a body length of over 75 mm.
  • Mice have good senses of smell, taste and hearing, however they have poor vision and are colour-blind.
  • Mice generally move along scent-marked trails and use their long sensitive whiskers as sensors when moving at night.
  • Average life span of only a few months in the field because mortality is high even in favourable habitat.
  • Mice are active at night and feed from several sites around the nest. Mice are seldom seen during daylight unless they are at high densities.

When do mice breed?

  • Females reach sexual maturity at 6 to 10 weeks of age.
  • Conception to birth is 19-21 days and mothers can re-mate immediately after giving birth to produce up to 10 litters per year under ideal conditions.
  • Mice can breed at any time if food is available.
  • In Australia, breeding peaks in spring/summer while there is abundant high protein food from insects, seed and growing plants.
  • An extended breeding season can allow mice to reach plague proportions in just one season but it can take two seasons for a plague to develop.
  • Average litter size is 5 to 6 but can be as high as 13.

ONE BREEDING PAIR CAN PRODUCE 500 MICE OVER A FIVE MONTH PERIOD UNDER IDEAL CONDITIONS.

Can mice swim and climb?

  • Mice are excellent swimmers and can remain under water for several minutes.
  • During floods adults may move to dry places abandoning newborn mice.
  • Light rain does not kill many adult mice.
  • Mice can dig, can vertically jump up to 40 cm, can fall at least 2.5 m without injury, and can squeeze through openings as small as 6 mm wide.
  • They climb almost any rough surface including ropes and electrical wires.
  • Normal rain seldom penetrates to underground nest sites.
  • Depending on soil type, mouse burrows can withstand heavy rainfall.

ONLY PROLONGED FLOODING AFFECTS MICE IN THE FIELD.

What does the average mouse eat?

  • Adult mice consume about 2-3 g of food per day.
  • Mice are omnivorous and in the field survive mainly on grass seeds, cereal and legume grains.
  • Their diet also includes insects, snails, earthworms, plant tissue and some fungi when available.
  • Usually, mice do not need to drink as they can obtain sufficient moisture from their food.
  • Mice chew the heads off stems, partially eat seed heads, remove newly sown grain, stunt early crops, chew machinery wiring/electrical fittings and contaminate storage areas.

THE IMPACT ON CROPS IS MUCH GREATER THAN JUST THE FEED MICE CONSUME.

What causes reductions in mouse numbers?

  • Frosts and cold weather do not necessarily kill mice, but may restrict population growth.
  • Nutritional stress can reduce abundance and may make mice more vulnerable to disease. However, if mice can remain warm and well fed in their insulated subterranean nests, extreme environmental conditions may not have much impact.
  • The main causes for collapse when densities are high are the cessation of breeding, exhaustion of food supplies and spread of disease.

An integrated approach to reduce risks

While baiting is effective in stopping damage in crops, there are also preventative measures to minimise the risk of mouse numbers rising. This is called Integrated Pest Management (IPM). An integrated approach, such as monitoring mouse activity, removing mouse harbour and reducing the feed supply can help prevent numbers building up in a range of crops.

MOUSE MANAGEMENT SHOULD BE PROACTIVE RATHER THAN REACTIVE.

Tips to help minimise mouse numbers rising:

  • Remove surface shelter by slashing, burning or herbicide treatment of grass and weeds along fence-lines, roads and around sheds.
  • Use galvanised mouse barriers to protect pig, poultry and storage facilities.
  • Consider changing the crop rotation to reduce the number of mice maintained over a long period of time.
  • Avoid planting in dry soil if there are signs of mouse activity. Sow when soil is moist enough to allow rapid germination.
  • Sow to an even depth (as deep as agronomically possible) if mouse numbers are high. Do not over bury seed.
  • Cross-harrow, diagonal roll or prickle chain after sowing.
  • Use harvesting techniques that minimise grain loss. Use crop lifters and knife guards, harvest at slow speed, set combs and sieves to minimise shatter and seed loss, use airfronts or flexifronts for pulses and fit screens to capture broken and pinched grain and weed seeds.
  • Minimise shattering of pods and seed heads when windrowing.
  • Graze stubble after harvest to reduce the residual grain and harbour (but leave sufficient cover to minimise erosion).
  • Where soils are not prone to erosion, mulching stubble after harvest exposes mice to predators and buries spilt grain.

If mouse numbers rise despite IPM measures, use MOUSEOFF® Zinc Phosphide Bait strategically to remove the base population of mice BEFORE damage occurs. MOUSEOFF® Zinc Phosphide may also be used to overcome a severe established mouse infestation.

Animal Control Technologies
46-50 Freight Drive
Somerton, Victoria, 3062
Australia
Telephone +61 3 9308 9688
Fax +61 3 9308 9622

E-mail: enquiries@animalcontrol.com.au