New Zealand's native moths and butterflies are facing mounting challenges, with 60 years of world-leading evidence pointing to significant species declines in the eastern South Island.
Their decline matters because as well as being a much-loved part of the natural environment, moths and butterflies are well-known pollinators and food for birds, and an essential part of ecosystems.
An independent panel of experts has assessed the conservation status of 498 Lepidoptera (moths and butterflies) species, in a new report published by the Department of Conservation (DOC).
Since the previous moths and butterflies assessment in 2015, 35 species have deteriorated in status, with six of those moving to Threatened – Nationally Critical (the last category before extinction). Although another 19 species have improved status, this is due to more knowledge rather than genuine improvement.
Panel member and DOC Senior Science Advisor Eric Edwards says the 60 years' worth of evidence in a moth study from Canterbury is rare worldwide, providing relevant insights into moth population trends.
"The 60-year record shows an 82 per cent decline of moths in the two Canterbury sites between 1961 and 2021. This result is compelling and is worrying evidence of serious moth declines.
"Unfortunately, this trend of a decline in moth species is likely to be ongoing in many other parts of New Zealand and around the world."
The panel found that the biggest pressures on moths and butterflies come from changes to their natural habitats, caused by invasive plants and animals, as well as the growing impacts of climate change in recent decades.
Eric says among more naturally open areas, particularly the eastern South Island, habitats that historically hosted native moths are being outcompeted by exotic grasses, exotic broom and wilding pines.
"Invasive animals are a problem too. Wasps are eating moth and butterfly caterpillars. More research is needed to better understand the seriousness of wasps and other invasive predators like mice."
Eric says it's not all bad news for moths and butterflies, and exciting discoveries are being made.
"A Swedish tourist's rediscovery in 2024 of the large and striking frosted phoenix moth was a sensation. Since then, several sightings have been reported in Rakiura, Little Barrier Island and Pureora Forest Park.
These sightings are largely thanks to the use of ultraviolet LED technology, which works in damp weather when frosted phoenix like to fly."
Eric says there are community groups and private landowners taking pest plants seriously, which is vital for the restoration of moth habitat.
"Citizen scientists are also making a difference. In the last few years, members of the public have used their mobile phones to record and upload vivid and detailed images of secretive and rare moths and butterflies to the iNaturalist app, increasing local knowledge."
Eric says anyone can become a citizen scientist by downloading the iNaturalist NZ app.
"Recording your sightings of moths and butterflies helps scientists, environmental agencies and community groups to better understand New Zealand's Lepidoptera and plan restoration work.
"Other naturing activities that everyday people can do include plant nectar species as food for moths and butterflies, get rid of invasive weeds, and control exotic wasps."
Read the report: Conservation status of Lepidoptera (moths and butterflies) in Aotearoa New Zealand, 2025
Background information
New Zealand has close to 2,000 moth and butterfly species. They are Lepidoptera, which means adults have tiny, often beautifully coloured, scales on their wings and drink nectar. Some moths are active during the day like butterflies, but most are active at night. A species may specialise for a particular part of a particular plant (eg flowers, stems, shoots, roots, leaves) or dead wood or moss.
The data showing the decline in Canterbury came from scientists sampling moths using a standard light trapping method from two mid-Canterbury sites in 1961-63, 1987-89 and 2020-21.
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