Find out how to run a rat and stoat monitoring operation. Use your results to track progress and make improvements.

The key to monitoring over time is consistency. Getting the basics right from the start will ensure you can compare your data year-on-year to show useful trends for your project.

The information on this page is designed primarily for basic rodent monitoring. For those looking to monitor for mustelids specifically, download our Practical Guide to Trapping booklet (PDF, 6,277K) or our Guide to monitoring rodents and mustelids (PDF, 788K). For more information, talk to your Predator Free Ranger.

A volunteer baits a tracking tunnel with peanut butter.
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

  1. Remove any scat or detritus.
  2. Place a fresh pre-inked paper in the tunnel, unfolded.
  3. 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

A volunteer in a bright orange shirt writes notes while crouched next to a tracking tunnel - a rectangular wooden box.
Collecting tracking tunnels in the field
Image: DOC 

  1. Remove each paper, turning it so the exit edge is at the top.
  2. Write the tunnel number along the top.
  3. Keep the papers in order as you collect them.
  4. Make notes:
    1. If there are no tracks, record whether the bait was taken.
    2. 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. 
    3. If there’s fresh scat in the tunnel, note the species as present just as if there were footprints. Remove the scat.
    4. Note anything else unusual, such as tunnel disturbance.
  5. Remove the bait.

Finish processing back at your base

  1. Spread any damp papers out to dry.
  2. Identify and double check any predator footprints.
  3. Update your notes.
  4. 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)
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