Transect walks record the numbers and locations of native and introduced Lepidoptera, helping track population changes over time. Effective monitoring relies on people first being able to identify NZ’s butterflies and day-flying moths.
Developed in 1973 by the UK Centre of Ecology and Hydrology, transects provide long-term data that reveal trends and early warnings of decline. Walkers record butterflies seen within an imaginary “box” around them, keeping the method and route consistent each year for reliable results.
Chrissie Ward in Nelson has been walking a transect regularly since 2009. Her walk is around and the decline in (a) monarch butterflies and (b) overall Lepidoptera species over this period is alarming.
The long-term monitoring of our butterflies through recording transects will be very useful and we will train you to do this... whether it's a 1 km or 10 km walk, close to your home or somewhere where you walk regularly. We have an app. set up to help you keep records. The important thing is being consistent over a number of years that you walk your transect.
Results from Nelson as at 14 March 2026
Report on Nelson Transect, March 2026
