How to Set Up Chew Cards and Tracking Tunnels

A practical guide to identifying pest species before control begins

When it comes to pest control in Aotearoa, one of the most important steps is often the one people skip: identifying what’s actually there.

Before any toxin, trap, or control method is used, we need to understand which species are present, how active they are, and where they’re moving. This is not just about effectiveness – it’s about doing pest control responsibly.

At Connovation, we believe good monitoring is part of good kaitiakitanga. By using simple tools like chew cards and tracking tunnels, we can make smarter, more humane decisions that protect our taonga species while avoiding unnecessary toxin use.

This guide walks you through exactly how to set them up, step by step.

Why monitoring matters first

Different pests behave differently. Rats, mice, and possums all interact with bait and traps in their own way – and using the wrong control method can lead to poor results or unintended impacts.

Monitoring tools help you:

Confirm which species are present

Measure population activity

Identify hotspots and movement corridors

Track success over time

Done properly, monitoring reduces guesswork and ensures any control programme is targeted, efficient, and humane.

What are chew cards and tracking tunnels?

Chew cards

Chew cards are small, baited cards designed to attract animals to bite them. The chew marks left behind can be used to identify the species.

They’re simple, low-cost, and highly effective for detecting rodents and possums.

Tracking tunnels

Tracking tunnels are enclosed devices that contain an ink pad and a tracking card. When an animal walks through the tunnel, it leaves footprints on the card.

These footprints provide a clear record of which species are present.

When to use each method

Chew cards: Great for quick detection over larger areas, especially for rats, mice, and possums

Tracking tunnels: Ideal when you need more precise identification (e.g. distinguishing between mouse and rat activity)

In many cases, using both together gives the best picture.

Step-by-step: Setting up chew cards

Chew cards are one of the most sensitive and cost-effective monitoring tools available. They can detect pest presence even at low densities and are widely used across Aotearoa by community groups, landowners, and programmes like TbFree.

1. Choose your location

Place chew cards where pests are most likely to travel or feed:

Along bush edges and fence lines

Near compost bins, fruit trees, or waterways

Around sheds, rural buildings, and shelter belts

Along natural animal runs

The goal is to intercept movement, not just scatter cards randomly.

2. Set the correct height and angle

Attach chew cards to a tree, stake, or post:

Ideally 15–30cm above ground (higher if livestock are present)

Fold the card in half to create a protective ‘tent’ shape

This makes the card more attractive and easier for animals to access while keeping it sheltered. 

3. Space your cards properly

Spacing depends on your goal:

For presence/absence monitoring:

Around 50m spacing in bush

Up to 100m along shelter lines

For detailed sampling or research:

20–50m spacing along transects

Consistency is key – repeatable layouts allow you to track trends over time. 

4. Leave cards undisturbed

Leave chew cards out for up to 7 nights.

Avoid checking them too early – minimal disturbance gives more reliable results.

5. Record results carefully

When collecting cards:

Label each card or location

Photograph chew marks

Record species codes (e.g. R = rat, P = possum, M = mouse)

Map results (e.g. GPS or Google Maps)

This transforms simple monitoring into long-term, meaningful data. 

6. Identify chew patterns

Different species leave distinct signatures:

Mice: small, fine parallel grooves

Rats: deeper, paired bite marks with wider spacing

Possums: rough, torn edges with irregular bites

Multiple species: overlapping or mixed patterns

As shown in the chew card guide, recognising these differences allows you to confidently identify what’s present before acting. 

Pro tip: consistency matters

If you’re monitoring over time (e.g. year-to-year), try to:

Use the same locations

Monitor at the same time of year

Keep spacing consistent

This ensures your data reflects real changes in pest populations – not changes in your method.

Step-by-step: Setting up tracking tunnels

1. Prepare the tunnel

Insert the tracking card and ink pad inside the tunnel according to instructions.

Ensure the ink is fresh and evenly applied.

2. Position the tunnel

Place tunnels in similar locations to chew cards:

Along natural runways

Under cover (logs, shrubs)

In sheltered areas

Keep them level and stable.

3. Add lure

Apply a small amount of lure (e.g. peanut butter) in the centre of the card to encourage animals to walk through.

4. Set spacing

Standard spacing is 50 metres for general monitoring

Closer spacing for high-resolution data

5. Leave overnight

Tracking tunnels typically only need one fine night to collect results.

6. Identify footprints

Common indicators:

Mice: tiny prints with close spacing

Rats: larger prints, longer stride

Mustelids: bounding patterns with paired prints

Use a tracking guide to confirm species.

Common mistakes to avoid

Even simple tools can give misleading results if used incorrectly.

Placing devices too far apart

Setting them in exposed or disturbed areas

Using too much or too little lure

Not recording results consistently

Monitoring is only useful if it’s repeatable and reliable.

Turning insight into action

Once you know what you’re dealing with, you can choose the right control method.

At Connovation, that means selecting target-specific, humane solutions – whether that’s first-generation anticoagulants like diphacinone, high-dose Vitamin D₃, or modern actives like PAPP for specific predators.

Just as importantly, it means avoiding persistent toxins like brodifacoum, which can accumulate in the environment and impact non-target species.

Monitoring ensures any control you use is proportionate, targeted, and responsible.

Final thoughts

Chew cards and tracking tunnels are simple tools – but they play a powerful role in protecting Aotearoa’s biodiversity.

By taking the time to monitor first, we’re not just improving results. We’re practicing better kaitiakitanga – making decisions that respect both our whenua and the species that call it home.

Ready to get started?

Explore Connovation’s monitoring tools like the Black Trakka tracking tunnel and start building a clearer picture of what’s happening on your land.

Because better information leads to better outcomes – for you, and for nature.