Rats

Norway Rat  Rattus norvegicus and Black Rat Rattus rattus

There are three species of rat in New Zealand. The Brown Rat or Norwegian Rat (Rattus norvegicus) the Black Rat or Ship Rat (Rattus rattus) and the Kiore or Pacific Rat (Rattus exulans). The Black Rat is the more commonly encountered rat pest. However, the Norwegian Rat is increasingly common particularly in urban areas and may come to displace the Black Rat as it has done in the other parts of the world. It is sometimes difficult to identify which species you might have. Even a young rat can easily be mis identified as a mouse. If you want to know which species you have an infestation of try the ID Table below.

The Rat is the most successful of all the world's pest animal species. In spite of centuries of conflict with man and numerous other predators it continues to adapt and survive.

The Black Rat is a major pest in New Zealand and is the common rat in the NZ bush and in the roofs of NZ homes. Norway Rats are more often found living in borrows around waterways and in the industrial parts of our cities. It is sometimes referred to as the Water Rat.

Although both species of rats are good climbers, the black rat is smaller and particularly agile. It is this rat that most often found in the roof spaces of NZ houses.

Rats are omnivorous with a strong preference for grain, fruit and vegetables.

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Click here for information on mice

How to get rid of Rats

1. If you have seen rats or mice, or evidence of them around your property, the most efficient and effective way to get rid of rats is to use rat poison baits (or non-toxic bait) sometimes in conjunction with simple traps and proofing.
2. NO Rats & Mice rodenticide bait is placed at strategic, safe points, inside and outside the buildings, in order to reduce populations around the building and to deal with individuals that enter, before an infestation can take hold. The NO Rats & Mice Weatherproof Blocks is a rat bait well suited to using outside or in damp areas while NO Rats & Mice with Tracking Powder is ideal for use in dry areas inside the house. If you do not wish to use toxic rodenticide bait, Kiwicare Natural NO Rats is a bait that is harmful only to rodents. However it should only be used in dry areas where other food sources can be controlled.
3. NO Rats Traps are useful to use where poison rat baits cannot be placed or as a helpful way of catching rodents that are 'dopey' from taking bait. the rodents can then be removed without risk of causing an unpleasant smell.
4. A mouse can squeeze beneath a door if there is a gap large enough to fit a pencil a young rat is only a little larger than a mouse! Draft excluding brush strips, are an ideal method of proofing such gaps. However, there are almost always other possible entry points around any building. So it is always wise to keep fresh rodenticide bait in place in safe places such as the roof void so that any rodents that get in are dealt with before you know about them.
5. This is an important and often overlooked aspect of controlling pests. For example, rodents are what we would call agoraphobic, they fear open spaces, and like to be under cover. A wide clear area around a building will deter rodents from reaching and entering the building. And the removal of available food and shelter from within a building can have a powerful deterrent effect.

Testimonial - The story of 'Gerald' the rat.

Rodent control products - Rodenticide rat baits (toxic and non toxic), traps and tracking powder.

NO RATS AND MICE WEATHERPROOF BAIT BLOCKS

This is a great rat bait product for any area of the home, farm or industry as the blocks are unaffected by damp. The blocks can be used outdoors to prevent rats and mice going inside.  The blocks can be thrown into inaccessible areas such as roof spaces, under sheds and floors. Bait Blocks can be broken up into smaller pieces if required.

See our Testimonials

Available in packs of 160g and 480g.

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NO RATS AND MICE BAIT AND TRACKING POWDER

Innovative combination rat bait and tracking powder. This product is finely ground cereal baits which kill rats and mice.  The bait also clings to the rodent fur and is taken back to the nest and further ingested through grooming.

Rodents are very shy and prefer to eat in secluded areas.  Place bait in dry, sheltered, secluded areas, in close proximity to known areas of activity. 

Check bait daily and continue to top up until no further bait is being taken.

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NO RATS AND MICE BAIT STATIONS

The bait stations are designed to reduce rodent bait scatter, are easy to handle, can be fixed in place with staples or tacks, and ‘topped’ up with the NO Rats & Mice Tracking Powder as required. Open the bait station by twisting the lid to expose the bait.  Replenish bait stations as the bait is taken or replace with new bait stations. When no more rat bait is being taken, twist the lid to close the bait station and store until it is needed again.  With the lid closed the bait stations are waterproof.

The active ingredient, Coumatetralyl, has a cumulative action and small quantities need to be consumed on several days before symptoms of poisoning appear.  Because of the slow acting properties of the bait, no bait shyness develops.

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Poison Safety

All Kiwicare rat baits are first generation rodenticides which offer enormous safety advantages.  The cumulative action (4-5 days) gives ample time to administer Vitamin K as an antidote in case of accidental poisoning; and so they do not normally pose a secondary poisoning threat.

Non-Toxic Control

RAT AND MOUSE TRAPS

Spring loaded ‘original’ wooden rat and mouse traps. Dead rodents can be emptied from the traps and the traps re-used, or the rodent and trap disposed of in the rubbish.

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NATURAL NO RATS

Natural NO Rats is a 100% natural, cereal based, multiple-dose pellet rat and mouse bait that contains a unique type of cellulose that cannot be digested by rodents. The rodents  die by dehydration and heart attack.  It is non toxic to all other species – humans, pets, farm livestock and farm working dogs. If ingested by non target species, the worst effect observed from repeated feeding is slight constipation, and no toxicity results from one-off ingestion.

Natural No Rats is more humane than commonly used anticoagulants such as Brodificoum.

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Rats

The head and body of a Norwegian Rat can be up to 30cm but is normally around 20cm. The tail is usually shorter than the head and body, an adult can weigh up to half a Kilogramme, it has grey-brown fur and is lighter on the underside. Their droppings are 15-20mm long, coloured usually grey or black. The Norwegian Rat will build nests in any suitable enclosed, safe space but naturally digs burrows into the banks of rivers. It will often nest in the walls and roof voids of homes and other buildings.

The Black Rat is smaller and more agile than the Norwegian. The tail is usually longer than the body and head. It is a better climber than the Norwegian and often finds its way into buildings via poorly sealed eaves. New Zealand buildings are susceptible to infestation by Black Rats because of gaps under roofing in the eaves. Rats may find their way onto the roof by climbing overhanging trees. The Black Rat does not build burrows and will nest in trees or in the voids of homes and other buildings.

The Black Death, otherwise known as the plague, ravaged Europe and Asia between the 14th and 17th centuries killing hundreds of millions of people. It was the Black rat that transported the fleas infected with the bacterium Yersinia pestis. The fleas fed on the blood of the rats and of the people that they came in contact with, spreading the disease as they sucked.

Kiore are rare and now found only in Fiordland, Stewart Island and some offshore islands. They were brought to New Zealand by Maori settlers and have cultural and spiritual importance to Maori.

Classroom Clips Rats

• Females are sexually mature at 3 months.
• Gestation period is 3 weeks. The doe will often re-mate within 24 hours of birthing.
• Producing up to 7 litters per year (6 - 12 young in each). Average lifespan is 1 year.
• Approximate number of young produced by one pair and their offspring:
  • Year 1 is about 200. Assuming 50% female
  • Year 2 would see 100 x 200 = 20,000
  • Year 3 would see 10,000 x 200 = 2,000,000
• Luckily for us the attrition rate is astronomical. So only rarely do rat numbers escalate out of hand. But, given good conditions and a plentiful supply of food their numbers can rise very rapidly. And it only takes one individual to gnaw through a water pipe of electric cable to cause damage costing many thousands of dollars.
• Also, rats are known to spread diseases. Rats are carriers of Leptospirosis (Weil's Disease), Salmonella, Typhus and a host of others (Diseases Directly Transmitted by Rodents - Centre for Disease Control and Prevention).
• Over 550 species of rats are recorded world wide.
• Rats can jump 1 metre vertically and 1.5 metres horizontally.
• Rodent incisors (two up, two down) grow up to 13cm per year necessitating continual gnawing.
• Tails are longer than bodies and serve magnificently as a fifth leg and for balance.
• Rats serving as host carriers of the Oriental Rat Flea (Xenopsyzla Cheopis) were responsible for the spread of Bubonic Plague (Black Death) throughout Europe/Asia in the 14th Century resulting in the deaths of over 25% of the European population alone.
• Rats can exist for long periods of time without water by eating insects, fish, fruit and eggs, or any food with adequate moisture content.
• Rattus norvegicus is not a native of New Zealand.
• Rattus norvegicus is primarily omnivorous, secondarily carnivorous, sometimes cannibalistic.

Identification of rats and mice in New Zealand

Do not rely on photographs to identify rodents size and colours vary widely and photos can be misleading. You are unlikely to be able to examine the rodent closely and it is often only the evidence of droppings that you have to identify your infestation. The size and shape of these dropping can be a good indication of what rodent you have.

Sourced from:    The Handbook of New Zealand Mammals (1990), King (ed) Guide to the Identification and Collection of N.Z. Rodents (1996), Cunningham and Moors

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