Rats and feral cats
There are a number of animals in the Waikato region that are regarded as nuisance pests. These pests currently have a low priority control status. They either cause minor to moderate ecological or economic damage (for example hares), or are so widespread it is impractical and too costly for Waikato Regional Council to control (for example rats).
The animals detailed below are listed as nuisance pests under the Regional Pest Management Strategy. Although Waikato Regional Council does not carry out control on these species, we encourage land owners/occupiers to carry out control on their land, as there is potential for populations to increase.
Control of these species can often be carried out along with other pest control, such as rabbit shooting and placing bait stations for possums and rats. This factsheet identifies the more common nuisance pest species in the region and outlines a number of control methods which are available.
Find out more about nuisance pests in Waikato Regional Council's Regional Pest Management Strategy (RPMS), including information about rosellas, feral pigs, feral dogs and feral deer.
There are two introduced European rat species in New Zealand, the Norwegian rat (Rattus novegicus) and the ship rat (Rattus rattus).
Rats are a threat to breeding birds as they prey on eggs and chicks. Ship rats are a particular problem as they are exceptional tree climbers. Our native birds have not evolved with rats and have no defences against them. Many native bird species also breed very slowly and can not keep up with the present rate of predation.
The Department of Conservation carries out rat control in areas where there are endangered native species, such as kokako and blue duck. The aim of this control is to keep rat numbers low enough to allow eggs to hatch and young birds to fledge. In areas where rat control has taken place, there have been observations of great recovery of seedlings, indicating rats also have an impact on vegetation.
Rats are widespread throughout the Waikato region.
Poison pellets in bait stations is an effective method to control rats. Rat poison can be purchased from your local farm supply store. A bait station can be made out of a piece of drainage pipe (that does not have drainage holes along it) or similar material. The station should be around 50 cm long and large enough that the rat can walk inside it but other animals such as small family pets or birds can not enter it. Fix the tube to the ground or tree branch using U-shaped wire. Place 4-6 pellets in each bait station. Check your bait stations regularly and remove any mouldy or wet bait. Bait stations should be ideally placed at 100 metre intervals.
If you are also carrying out possum control you can use a possum bait such as Pestoff TM, which is also effective on rats.
Note: rat poison (and possum poison) can be harmful to dogs and cats.
Ensure your bait stations are in an area your pets or domestic stock do not have access to. Follow the instructions and safety precautions on the packet. If an animal accidentally eats bait, call your vet immediately. The antidote for most rat poisons is vitamin K1.
Feral cats (Felis catus) are domestic cats that have gone wild or have been bred into the wild. They often look scruffy and may be very wary of people. Cats prey on birds, lizards and frogs, including many native species. Cats can carry tuberculosis, toxoplasmosis and parasites which are harmful to humans.
Feral cats live in a wide range of habitats throughout the Waikato region. They are very territorial and have home ranges from 30 hectares to 80 hectares in size. Feral cats are mainly active at night.
Controlling feral cats
Feral cats are naturally cautious and can be difficult to trap. Live catch traps, such as box and cage traps, are suitable.
As cats are more active at night, set your traps at night and release them in the morning if nothing is caught. This is a good safety measure if you have domestic cats around, as you only need to keep them inside during night hours.
Wire your traps open for a couple of nights so the cat gets used to entering it, then set it to catch. Bait the traps with fish, fresh meat or cat food. Once trapped, a feral cat should be disposed of humanely. Check with the SPCA for approved methods of destruction in your area.
Legal Requirement: all 'live capture' traps must be checked daily.
Shooting (in rural areas only) may be effective provided the animal is killed on the first attempt. This is because a feral cat will quickly escape and be very wary from then on. Talk to your family and neighbours and advise them to keep pets inside if this option is suitable for your area. It may be a good idea to put high visibility collars on your domestic cats.
For additional advice and information and to obtain pest control products, contact your local farm supply store or nearest Biosecurity Animal Pest Contractors for the Waikato region.