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Mice (Mus dsomesticus)

Environmental Health

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Mice

Mice are one of the most common pests found in domestic premises.  They are part of the Commensal Rodent group, which means that they are well adapted to living in harmony with man in his own environment.  They spread various diseases such as Salmonella and Dysentery and can cause structural damage to premises by the constant gnawing on wood, cables, pipes and household items.  Because of their feeding habits mice are difficult to control.


Mice sometimes burrow.  They live indoors and outdoors but are almost unknown in sewers.  They nest generally within stored materials, under floorboards, in lofts, in furniture etc.  They are excellent climbers.  They are erratic in habit and inquisitive towards new objects.  Range 1.5 - 5 metres. They have an excellent sense of hearing, but their sight is very poor.  They are colour blind and can only make out shapes.

The life expectancy of mice is around one year during which time a female may breed up to six times. The average size of a litter is six. Breeding occurs throughout the year but especially in the spring and autumn

 

Feeding habits

Mice like to eat nibbles and prefer cereals. Consumes only 3-4 grams per day.  Unlike rats, can survive with very little water and often obtains sufficient water in food.

 

Evidence to look for

  • Mice droppings.  These are rod shaped and 3 – 6 mm long Fresh droppings will be soft and moist.  They will usually be black and each mouse can leave approximately 80 per day.  You could find them under your kitchen sink, in the hotpress, around central heating boilers, in lofts, etc.Fresh gnawing of wood, carpets, paper, cables, household items, furniture, etc.

  • Damage to foodstuffs, items in cupboards and lofts.

  • Smear marks – their  hair is oily and leaves a dark stain around well-used entry points and runs.

  • Live or dead mice.

  • A bad smell.

 

How to prevent mice

  • Mice only need a gap of 10mm to gain entry.  (The size of a penny)  Ensure that all gaps around external drainpipes, door and window frames, etc are filled in. 

  • Ventilation bricks and slots should already have a fine wire mesh incorporated in them.  If this has worn away, replace it externally with a fine insect mesh.

  • Gaps around heating and water pipes indoors and outdoors should be sealed with particular attention  given to water pipes from boilers. 

  • Self-closing door mechanisms should be fitted to back doors to ensure these remain closed as mice often enter premises through an open door.

  • Make sure that all food stuffs are covered in the house. 

  • The garden should be kept maintained and clean at all times.  Grass should be cut regularly and all weeds removed.  Long grass and weeds provide food and shelter for mice.  Garden sheds, etc. should be kept at least 25cm off the ground.

 

Bait

This is the quickest way to control mice in your property, but could result in a bad smell.

  • Make sure that you follow all the instructions on the packet

  • Ensure that children and domestic animals have no access to the bait.

  • Where possible try and put bait into holes, and under floorboards.

  • Because of their feeding habits, mice are constantly nibbling.  Use plenty of bait in many areas.

  • Inspect bait regularly.  Continue to top up bait until no more is eaten.

  • Remove all bait when problem is cleared. 

  • Most bait takes between 4-10 days to kill mice.  It will not kill them overnight!

 

Traps

  • Most adult mice know what traps are and how to get the bait out of the traps without getting caught.

  • If using traps, ensure that they are placed tight against wall/floor junctions.  Mice almost always run along these junctions. 

  • Use a chocolate covered cereal-based biscuit for bait. 

  • Remove dead mice from the trap and always reuse the trap.  Mice like the smell of their own kind and will be more inclined to go into traps that have been used.

  • Sticky glues are inhumane and not recommended.

 

If you feel that you cannot carry out this work yourself, the Pest Control Officer can do it for you.  There may be a charge for this service.