RATS AND MICE
The Adelaide Hills provide an ideal habitat for rats and mice due to the proliferation of vegetation, food and water. Complete control is difficult, however, a number of relatively simple measures can be taken to minimise problems. Rodents are destructive and can spread disease. They are most active at night although they may be seen during the day when numbers are high and food is in short supply. Apart from tell-tale droppings, rats in particular may be indicated by signs of gnawing needed to control the growth of their teeth, oily smears from their coats along walls used for guidance due to their poor eyesight, burrows and worn tracks in undergrowth.
The best control method is to prevent rodents gaining entry to your home or business. This is best considered at the construction stage, however you can still block entry by sealing gaps around windows and doors greater than 6 mm wide with silicon sealer, metal flashing or timber moulding sealing around pipe penetrations or flues with mortar, metal sheet or fine metal mesh (mesh size less than 6mm) using pipe guards on downpipes and flues to prevent rodents from climbing using rodent proof fencing, or elevated grain storage in rural areas smooth rendering walls down to the floor or providing a 150 mm strip of hard gloss paint at the base of walls, again to prevent rodents from climbing providing steel kick plates at the base of doors and door frames to prevent gnawing using single leaf construction in food stores to prevent access through the cavity.
You can encourage rodents to move elsewhere by making your property an undesirable place to live. An undesirable habitat is created by cleaning up all spills of food or water, however small storing grains or foods in sealed plastic or metal containers storing grains or foods at least 200 mm off the floor removing all rubbish and waste removing weeds and long grass pruning trees and shrubs off the ground and at least one metre from buildings storing building materials and timber in tidy stacks, avoiding formation of cavities removing water sources such as water bowls for pets, dripping taps, pooling in poorly-fitted guttering and saucers under pot plants screening access points to rainwater tanks and over garden ponds.
USE OF BAITS AND POISONS
Extreme care must be used when handling baits and poisons as they are generally toxic to humans and household pets. Always read and follow the directions on the packaging. Anticoagulant poisons are commonly used, with active ingredients including Warfarin and Coumatetralyl. These require feeding over 5 to 7 days to reach the lethal dose, and they present a reduced risk to pets should they be consumed accidentally. The most effective rodenticides are the new single dose products containing Bromadialone or Brodifacoum, however, the risk to pets is increased.
All solid baits are best used inside bait stations, for the protection of pets and to encourage the rodents to feed where they feel protected. This may be a manufactured bait station or an improvised box, tube, pipe or bag with an entry and exit point. The bait station should be located in a dark, protected area with all other food sources removed.
A simple and safe home made bait is a 50:50 mixture of dry cement powder and cornflour placed in a shallow dish or bait station in the path used by the rodents. It is particularly good for use indoors, as the rat or mouse will feed then seek water outside. Water causes the cement powder to react, quickly killing the rodent outdoors where it can be disposed of easily.
Liquid form rodenticides may require mixing with water or food, including (in order of preference): raw meat or fish, rolled oats, wholemeal breadcrumbs, tinned meat or fish, cooked cereal, cheese, cooked meat scraps, powdered milk, fresh fruit or vegetables especially apple, and cooked vegetables. Finely chopped baits are best as this prevents the rodents from carrying them away to where other animals may find and eat them.
These foods can also be used in traps which are suitable for use where only a small number of rodents are a problem. Traps are also safe for use where pets are around. Set the traps in dark corners with the trigger side close to the wall, using a number of traps similar to that of the anticipated number of rodents.
Where bait stations are used, they should be checked at least every other day and replenished as required. Baiting should continue until the bait is no longer being taken. Tracking powders are another alternative. These rely on the rodent picking up the powder on its feet and fur, then ingesting the poison in grooming itself. Tracking powders may be useful where it is difficult to remove the alternative food sources. Where the infestation is large, the most effective approach is to employ the services of a professional pest control company.
For Further Information Contact
ENVIRONMENTAL HEALTH UNIT
ADELAIDE HILLS COUNCIL
Telephone 8408 0400
Fax 8389 7440