Quick, Clean Kill Key to Effective Rodent Trap 

Part of the national drive for Predator Free 2050 is the control of rodents. Every land manager and owner has a role to play. If enough of the population take up the challenge and participate, we can expect numbers to fall.

Rodents including the Norway rat, the roof rat and house mice are pests when they infest properties and threaten public health. They can damage or destroy critical habitats, native plants and animals, crops, property and food supplies. 

Estimates of rat populations vary but because rats reach sexual maturity after 9 weeks, a population can swell from two rats to around 1,250 in one year. An estimated 25 million native birds are lost to predators every year. The challenge is to save our birds and native fauna so future generations will hear the song of our native birds. Rodents are not restricted to rural areas and many of our towns and cities have high populations of rats and mice. 

Community groups are having success in reducing numbers, the proof being the proliferation of native bird species in their controlled areas. Trapping in an urban setting can be effective with just one trap per property, if enough of the community is involved. In a rural setting it is important to have traps in lines with 50m between traps and 100m between lines. In difficult terrain it is best to set lines down ridges and spurs and along contours to achieve the necessary spacing. Traps are best placed in a tunnel to both protect the trap and to direct the rodent into it.

Traps have been used for generations but some are not fit for purpose. While they are cheap to buy, the chances of them killing a rodent quickly and effectively are slim. Large rats can become both bait-shy and trap-shy if they eat a sub-lethal dose or escape from traps they set off. Large Norway rats can exceed half a kilogram in weight and for this reason, traps need to be robust and have enough killing power to achieve a high degree of success.

Traps can be assessed by their level of humaneness and capability. The National Animal Welfare Advisory Committee (NAWAC) tests traps to rigorous criteria and will give them a pass or fail. One trap that has passed is the Tom Cat Rat Trap, which is available through Farmlands.

The rigorous testing helps to inform consumers if traps can kill humanely and that a caught rodent will not escape and become trap-shy. One tunnel option is the Tomcat trap tunnel, which holds two traps and can be placed vertically or horizontally and easily held in place with a cable tie. 

Tomcat traps are easy to use and can be deployed in both rural and urban environments. Setting the traps can be done with your foot or hand and the removable bait cup allows easy filling and replacement of bait before setting. Being relatively inexpensive, a number can be placed as a protective barrier to protect buildings or susceptible areas from rodent entry. Use of traps can assist a baiting programme if rodents have started to become bait-shy or if baits are not a considered option.

Always set traps in places where rats are frequenting and is in their pathway. This will often be against a wall, on a pipe or rafter or on a pathway. Checking for rodent sign will be helpful in determining where to set the traps for best results.