Rats and Mice

Why rats and mice are a problem

In addition to transmitting disease, rats and mice can cause a host of other problems:

  • When rats and mice take up residence in buildings, including people's homes, there will usually be a build-up of droppings, straw, and other bedding material. These can harbour disease and other pests, and are also a potential fire risk.
  • Rats and mice will gnaw at timber structures and even copper water pipes, which can have costly consequences for building owners.
  • The parasites they carry include fleas, mites and a range of other insects - which can also transmit disease and make life extremely unpleasant for humans, domestic animals and livestock.
  • Mice in particular are able to access food areas easily and contaminate the surfaces they cross over and food they access.
  • If this isn't enough, rats and mice will breed in ceiling insulation - rats have enough body mass to compress some insulation materials, reducing their insulation properties.


Preventing rats and mice infestations

There are several things you can do to help reduce the risk of rats and mice becoming an issue in your home or on your property:

  • Keep food scraps in vermin proof containers and clean up food after feeding pets and animals.
  • Seal up possible access points around waste pipes and plumbing where they pass through foundation walls and exterior wall linings.
  • Trim trees so rats and mice are prevented from climbing onto roofs and accessing roof spaces.
  • Keep garden areas tidy. Vegetated areas should be thinned out to allow inspection and not overgrown.
  • Having animals such as poultry (hens, ducks) and pigs increases the risk of having a problem with rats and mice as they will be attracted to any food scraps or grain left after feeding. If you do keep animals, good housekeeping is essential to reduce this risk. Keep food in sealed hard material containers that are vermin proof - such as plastic paint containers - and store them in a vermin proof building.
  • Where you need to resort to using bait, follow some of the basic rules in dealing with rat and mice infestations section.


Dealing with mice infestations

If you do have a problem with mice, using traps and bait can be an effective way to eradicate them:

  • For small mice infestations use a trap with bait well fixed to the loading mechanism.
  • For small mice infestations where bait is the preferred control method use a tin lid with at least a 10 mm rim to contain the bait. Top up bait until feeding stops.
  • For both the above methods locate the bait station or trap in a location that is frequented by the mice - behind the oven, ceiling space etc. Make sure it's easy to access the bait station so that a top-up and inspection is straightforward.

Dealing with rat infestations

Using bait to eradicate rats can be more difficult as rats are highly intelligent and may not enter a bait station. However, the following methods generally work very well:

  • For ceiling and/or roof space infestations a commercial bait station can be located in the ceiling space and 'loaded' with a pellet bait. Rats are sometimes wary about entering a purchased bait station that has an entry portal, so if after one or two days the bait remains untouched use the below method instead.
  • Rats will often transport and store the bait for later consumption so it's important to fix the bait to the bait station. Make up your own bait station by cutting a piece of wood (100mm x 50mm x 400mm). Hammer four 150mm nails 20mm into the wood equally spaced along its length. Purchase 'ring-doughnut' style pellet bait (eg Storm, Talon) and place the bait rings over the nails (four rings per nail is a good rule of thumb). This will stop the rats carrying the bait away. If the bait rings do not have clean holes drill the centres out. Remember to use gloves when handling the bait. Place the bait in an area that provides the best access for topping up and inspection but locate it in an area where you think the rats are traversing. Check daily and top up until consumption stops. This may take up to five days.

For large infestations you may need to bring in a professional contractor. For people on lifestyle blocks, where rats are entering other buildings, you may see rat burrows if the infestation is extensive and need to adopt a more sophisticated approach to eliminating the problem. This may need to be carried out over a prolonged period as the local rat population could be quite large.

Where infestations get out of control

Controlling rats and mice where large populations may be present, especially in well vegetated urban environments, can be challenging and you may need to contact Council to investigate the use of a professional service to eradicate, or at least significantly reduce, the local mouse and rat population.

If you are concerned about rat and mice populations in an urban area, please contact us.