What does it look like?
House mice are small and eat a wide range of foods. They typically weigh up to 30 grams and measure about 115 mm in length, not including the tail. House mice have a dull grey-brown back, a uniform grey belly, a thin grey-brown tail, and large black eyes.
Why is it a problem?
Since being introduced to New Zealand, mice have had significant impacts on native flora and fauna. Caterpillars, spiders and weta are a major part of the mouse's invertebrate diet. They also eat a range of seeds, including hard beech, mountain beech, kauri and rimu. Seed consumption can prevent these species from regenerating.
A reduction in invertebrates may also have wider effects on vegetation by disrupting natural ecosystem processes.
Along with rats, mice eat and damage crops, contaminate and damage human and animal food, damage buildings, and carry diseases such as leptospirosis. Rats and mice defecate and urinate as they travel, leaving urine stains and droppings.
They can be found from the coast to altitudes up 1,300 m, predominantly in temperate forest (native and exotic), croplands and pasture, and subalpine tussock. They also occur in various urban habitats. House mice are very well adapted to dry conditions due to their ability to concentrate their urine, and as most of their water requirements can be taken from the moisture of their food.
House mice are common rodents in Hawke’s Bay. They prefer drier habitats and forested areas including forests, dunes, rivers, lagoons, and estuaries.
Mice are prolific breeders. Each year a mouse can produce up to 60 young.
Control methods
Poisons
Poisoning can be an effective method to control a house mouse infestation or to achieve control over a large area. Most rodent poisons are anticoagulants and following a lethal dose (often a from single feed), mice generally die within seven days.
It’s recommended poison baits are placed within purpose-built bait stations to protect bait from the weather and protect non-target animals (like pets and birds) from feeding on bait directly. Placing bait in bait stations will help prevent mice removing bait and storing in other locations. Check bait stations regularly - if all the bait is gone within the first night of baiting, more bait stations are required. Remove any mouldy bait and replace with fresh bait. Wear gloves when refilling a bait station for your own protection and to minimise putting human scent onto the station and the bait within.
Always read the label before using poison. Make sure you follow instructions and understand the symptoms of accidental poisoning and how to treat it.
Put baits in secure places away from children, pets and stock.
In case of accidental human consumption, contact the National Poisons Centre on 0800 764 766 for advice.
Rodenticides can be extremely harmful to dogs and cats. Symptoms can take several days to appear. They may include lack of appetite, lethargy, bleeding from the nose or mouth and pale gums. Vitamin K can be used as an antidote. Call your vet immediately if an animal accidentally eats rat bait.
There are a wide range of baits and bait stations available for purchase from local retail, garden and farm supply stores or from online suppliers.
Trapping
Trapping is best suited to small mice infestations in and around buildings. It’s particularly suitable in buildings, where using poison and having mice die inside is not ideal. Trap covers can be made out of coreflute (the material that real estate signs are made of). These keep the lure dry and prevent other animals being caught. These should be blocked at one end and tall enough that your traps can operate properly. Traps need to be checked and lured regularly. Peanut butter works well as lure.
Traps used to kill mice include modified Victor Pro trap with tunnel, Victor Pro trap with tunnel and Goodnature A24 rat and stoat traps.
Prevention
The presence of rodents can be a sign that a clean up of the house, shed, garage or section is needed. Clean up inside as rodents like old newspapers or magazines, boxes, rags and junk in cupboards, spare rooms, and basements. Mice can live behind the refrigerator, in the hotwater cupboard, or in any kitchen cupboard.
Outside, rodents like piles of bricks, timber, rubble, derelict cars or appliances, piles of garden rubbish, and overgrown parts of the section. Remember to rodent proof the compost. Seal all entrances into buildings and keep areas around houses and buildings clear as they like to travel along the edges of structures.
Hawkes Bay Regional Council is not responsible for carrying out mouse control.
Cats and dogs will not usually solve a rat or mouse problem and may only be successful in catching the odd one or two.
More information
Hawkes Bay Regional Council is not responsible for carrying out mouse control.
Related links
