Rats

Rats

Rats and mice are almost always present throughout suburban areas due to adequate food, water and shelter opportunities created by humans. Unfortunately they can never be eliminated but they can be controlled and all residents have a duty under the Health Local Law 2003 to ensure their properties are maintained to prevent rodent breeding. Rats can do considerable damage to buildings due to their need to gnaw on objects to keep their teeth short.

Signs of a rat infestation include:

• Droppings which are oblong in shape and about 12-20mm in length
• Remains of snail shells with the sides eaten out, nutshells, bones, seeds, etc. in the shed and other dark spots around the house
• Greasy marks along surfaces from rodent fur
• Fruit, vegetables and berries in the garden being eaten
• Burrow holes around buildings
• Damage to wood, soft metals, soap, food containers, conduit and cables from rodents gnawing on them
• Squeaking, gnawing or movement sounds in walls, cupboards, ceilings and under floorboards
• Pets being more excitable than usual
• Footprints and tail marks on the ground or along dusty surfaces
• Nests hidden in buildings made from rags, paper, cardboard, straw and other materials

Preventing rat problems

The presence and number of rats is determined by the availability of food and shelter. By denying the rodents these, you can effectively control rat populations. You can do this by:

• Removing fruits and nuts from trees when in bloom and collecting rotten fruit from the ground
• Trimming palm tree branches and remove their fruits 
• Keeping the backyard as clean as possible and free of debris and regularly removing garden waste and rubbish from sheds and around the yard
• Store wood off the ground and away from sides of sheds and fences
• Maintaining rubbish and compost bins in a good condition with secure lids and free from holes
• Keeping pet dishes clean and storing bulk pet food in sealed containers
• Cutting back trees away from the house to prevent easy access to the roof
• Blocking access holes into the house
• Ensuring disused containers are upturned so they do not collect rainwater

BAITING

The most effective way of eliminating rodents is to bait them using poisons. Many brands are available at supermarkets and hardware stores but look for rat bait with coumatetralyl, bromodiolone or brodifacoum as the active ingredient. To avoid access to pets and children, you can wire wax blocks to trees and higher areas or you can also purchase rodent bait boxes which seal the baits inside. Place baits along rodent paths, in the roof, shed and dark spots around the house such as behind the refrigerator. Ensure you place baits in visible areas so they can be easily checked regularly to see whether they have been eaten. Replace the baits regularly and maintain supply for at least two weeks after you notice no more has been eaten. Rodents can develop a tolerance to the active ingredient so you may wish to change the type you use if you find they are not working.

Remember to always keep baits out of reach of children. If ingested, contact the Poisons Information Centre on 13 11 26 (open 24 hours). Vitamin K can be used as an antidote.

TRAPPING

An alternative to baiting is the traditional method of trapping using two types of traps - the old-fashioned snap back trap and a plastic capture box. Different types of bait can be used including bacon rind, chocolate, fish, nuts, prunes, apples or peanut butter. Rats can be suspicious of new objects or surroundings so they may stay clear of the trap until it becomes familiar. Placing the trap in the path of a rat and hiding the trigger under straw or cardboard is one way to get around this trap shyness. Traps should never be set above food or food preparation surfaces to avoid contamination by urine, droppings or blood.

Rat facts

A rat can:

• fall 15 metres without hurting itself
• swim 800m
• tread water for 3 days
• jump 1 metre vertically and 1.2 metres horizontally
• wriggle through a hole one-quarter its own size
• gnaw through lead and aluminum sheeting
• produce up to 15,000 descendants in a year

Further information you can refer to the Department of Health brochure Facts on Rats.

If you are experiencing an increase in rodents around your property and you think it may be due to a neighbouring property, please contact Environmental Health Services by completing a Health Service Request form