
A tracking tunnel is baited with peanut butter
Image: DOC
Set up three weeks before
If you haven’t already set up your monitoring lines and tracking tunnels, do that first and wait three weeks:
Where to put tracking tunnels and lines
How often to monitor
Use your goal and management objectives to inform monitoring frequency:
- If you only want pest data at critical times, you could monitor during bird breeding seasons or before and after control operations.
- For ongoing studies, monitor four times per year: February, May, August and November.
- For a clearer picture of fluctuations across the year, monitor once per month or every two months.
Check the weather forecast
Weather will play a role in animal activities and may skew your results. Ensure each monitoring survey is conducted over one fine night.
Set-up day
This guide presumes you're using pre-inked papers. You can make your own tracking system with food colouring and a sponge.
Equipment list
- Pre-inked papers
- Bait: crunchy peanut butter
- Tools if monitoring any fixed-lid tunnels
- Personal gear
How to set a tracking tunnel
- Remove any scat or detritus.
- Place a fresh pre-inked paper in the tunnel, unfolded.
- Smear peanut butter generously on either end of the tracking card.
Collection day
After one night, collect the papers and process each tunnel:
Equipment list
- Notebook, pencil and optional shorthand reference table
- Optional: smartphone to record results using the Trap.NZ app
- Tools if monitoring any fixed-lid tunnels
- Personal gear
Process each tunnel in the field

Collecting tracking tunnels in the field
Image: DOC
- Remove each paper, turning it so the exit edge is at the top.
- Write the tunnel number along the top.
- Keep the papers in order as you collect them.
- Make notes:
- If there are no tracks, record whether the bait was taken.
- If you’ve mastered footprint identification, you can do that now or back at base:
See Gillies and Williams' footprint identification guide (PDF, 1,411K). If you need help, contact your Predator Free 2050 Ranger. - If there’s fresh scat in the tunnel, note the species as present just as if there were footprints. Remove the scat.
- Note anything else unusual, such as tunnel disturbance.
- Remove the bait.
Finish processing back at your base
- Spread any damp papers out to dry.
- Identify and double check any predator footprints.
- Update your notes.
- Bundle the papers, label with the survey area and date, and store for later reference.
Interpret the data
To calculate and monitor the abundance of pests over time, you can:
- use Trap.NZ to generate indices, maps and summary tables to export and share. You can also use their app to take notes in the field
- use scientific formulae to generate indices yourself. See the section ‘Counting the tracks, calculating the activity/tracking index’ in our guide to monitoring rodents (PDF, 788K).
Write and share a report
A formal report is a great way to release information to the public. Your results will be the star of the show, but include other information for context:
- Name of the location or block
- Size of the management area, especially if you have allowed for buffers around operational boundaries
- Control methods and start and finish dates
- Device type
- Number of lines
- Number of nights devices were deployed
- Weather information
- Names of participants (optional – get permission)
- Maps with data overlays (optional)