Trap rats • Urban Ark

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Rats are the single biggest threat to native biodiversity in suburban Auckland. A single pregnant female at the start of summer can lead to hundreds of rats. Significantly reducing their numbers has been proven to give native wildlife (and our urban ngāhere) a chance.

Aotearoa was rat-free until Polynesians brought the kiore here around 700 years ago. In suburban Auckland, the kiore has long been out-competed by bigger and more voracious European rodent invaders, the ship rat (black rat, roof rat or house rat) and the Norway rat (brown rat, common rat or sewer rat). Both the ship rat and Norway rat are widespread throughout New Zealand, but exhibit different behaviours and habitat preferences. The ship rat, the smaller of the two, is a great climber and spends most of its time in trees, while the larger Norway rat prefers urban environments and can be found on the ground near waterways, wetlands, and beaches.

Trapping rats

To effectively suppress rat numbers we need a rat trap in every fifth back garden, or every 50 metres in reserves.

Urban Ark groups trap rats using one of three types of trap. The Victor Pro and T-Rex both go in a wooden box, which keeps out little fingers, curious pets and non-target animals. The D-Rex Supervisor Max is an enclosed design used without a protective box.

Victor Pro

The most humane and effective option for trapping rats of all sizes. Setting this trap takes a bit of practice so check out this video to learn how.

T-Rex

The T-Rex is easier to set and perfect for school groups or less agile fingers.

D-Rat Supervisor Max

A slightly different approach is a D-Rat Supervisor Max which gives the option of targeting mice and can be placed directly in trees to target ship rats.

For a more general look at setting traps, check out this video. These are new traps so bare hands are fine, but once in the field you should always wear gloves to avoid rodent-borne diseases.

Basic rat trapping tips

Always wear gloves when handling your trap or catches. Gloves are important for hygiene and they also avoid transferring human smells, which can deter rats.
Check before opening the box if the trap is still set or not. You can always use a long stick to set off the trap before removing it from the box.
Only hold the trap from the back (away from the business end).
Bait your trap before you set it.
Peanut butter is the most common lure, but not necessarily the best. We’ve listed several alternatives below.
Use your thumbs to pull back the kill-bar to avoid accidents.
Make sure your trap/box combo is on level ground. Rats are put off by wobbly unstable boxes.
When putting your trap into the box, place it in bait-end first and slide the trap in until it’s just inside the box.
Your lure is likely to be stolen by slugs or insects after a few days. Refresh every few days!
To remove a rat from the trap, hold the trap over a bag or bin and pull up the kill bar so the pest drops out. See below for disposal.

Trap maintenance: check out Predator Free NZ’s Looking after your traps and Forest & Bird’s Maintaining your Victor rat trap.

Advanced Rat Trapping Tips

Curious but cautious

Rats are a mix of curiosity and caution, which makes them well adapted for survival. Anything you can do which makes them more curious and less cautious will help you catch them.

Try smearing peanut butter on the mesh at the front of the safety box and place a blob just inside the entrance. A taster of free bait with no associated negative consequences will make them much less cautious about entering the box and engaging with the bait in your trap.
Try scuffing up the ground in front of the box, as this can arouse curiosity.
Your lure will dry out after a few days and the aroma of peanut oil will diminish so don’t assume that just because it is set it is doing its job. You will only catch a rat if your trap has been freshly baited to ensure it is more alluring to passing predators than other foods available in their environment.

Limit alternative food sources

If rats aren’t hungry they won’t risk entering the box and trap. Make your trap the most appealing thing around by minimising other free food:

Shut rubbish bins lids securely.
Remove fruit, nuts, avocadoes etc from trees as soon as they are ripe enough to harvest
Stop composting for 2 or 3 nights (e.g. keep your compost in a sealed bucket in the kitchen temporarily) so rats get hungry and take more risks.
Avoid leaving cat or dog food outside.
Avoid feeding bread etc to birds.

Boost your trap appeal

Make a lure trail leading to your trap. You could use blobs of peanut butter, or whatever you have baited your trap with. You could also use small pieces of any fruit, nuts, avocados you’ve taken indoors. Rats will be looking for them and if you make it easy for them by removing skin or shells they’ll really lock onto the trail you’ve created.
Place the lure trail and the trap along a known rat run (usually along a wall or fenceline).
While rats are intelligent, they aren’t put off by the sight or smell of a deceased compadre. In fact, because they are social animals, they may actually be attracted to a trap that has recently had a dead beast in it…so while a well used trap can admittedly become a bit gross to us humans, it’s more likely to be enticing for the predators you are targeting.

What’s the best lure?

Choosing the best lure is a toughie! It all depends. And what works one day possibly won’t the next. As they say “tools used too often go blunt”.

Peanut butter A long-standing favourite and the mainstay of hundreds of reserve trapping groups and backyard trappers. Some say premium brands (such as Pic’s) work better than your cheapo brands with added non-peanut oils. Try mixing in some oats for a change. Peanut butter can often be taken by insects, sometimes overnight, but using ‘chunky’ helps ensure some is left for catching rats. Re-apply every few days.
Mayonnaise Some claim better success with mayonnaise than peanut butter.
Nutella These rats get fed better than we do!
Chocolate White chocolate buttons apparently gets the tick from your average rat.
Cheese The old mousetrap favourite but quickly goes off in the heat.

For some more ideas check out this handy advice from Predator Free NZ.

What do I do with a dead rat?

Firstly, make sure you’re wearing gloves. Apart from the yuck factor, dead rats (and other animals) transmit leptospirosis, a bacterial disease you don’t want to get.

If you can face it, smear the dead rat around the inside of the trap box, or leave the dead animal nearby. Rats are attracted by other dead rats.
When you’re finished with it, pop the dead rat in your bin. Think of them as meat scraps. Make sure you put your bin out for the next collection
Alternatively drop your dead rat in your compost bin and cover it with organic material, or bury it in your backyard - it will quickly break down.