Help provide more data to help our monarchs
Monarch butterfly enthusiasts can play a vital role in gathering data to support the conservation of New Zealand’s monarch population.
Our tagging programme was initially established to explore potential migration patterns within NZ monarchs. However, analysis in 2021 revealed no consistent migration patterns or common destinations. Most tagged butterflies were recovered near the area where they were released, leading to the project’s temporary pause.
A Brief History of Monarch Tagging in NZ
The tagging of monarchs in New Zealand began shortly after the formation of the Monarch Butterfly NZ Trust in 2005–06. By 2007, widespread tagging was underway, continuing for 13 years. Both anecdotal evidence and tagging data suggested that most monarchs overwintered near the area where they eclosed (emerged from their chrysalises).
What We Know About Overwintering
Reports of overwintering sites around NZ are at present sketchy. Dr Stephen Pawson and Dr Lisa Berndt researched monarchs overwintering in Christchurch in the early 2000s. You can see their report here. The information was utilised by the Christchurch City Council to create a map showing major overwintering locations but since the earthquake in 2011 many of these overwintering locations have changed.
The Future of Tagging: 2025 and Beyond
Tagging will resume in February 2025, likely running through May when monarchs are assumed to enter reproductive diapause and overwinter across the country.
We also hope to clearly identify more overwintering sites and encourage volunteers living in the vicinity to monitor the overwintering populations. It is assumed that these overwintering populations are in reproductive diapause. If so, a methodology could be put in place to enable population counts to be undertaken, observations made of flight patterns on warm, sunny winter days and any evidence of mating behaviour. This could be backed up with monitoring of swan plants for evidence of eggs and establishing whether they are fertile.
How tagging works
Each tag has a unique code number, prefixed by two or three letters indicating the year (e.g., T series = 2020). The tags are linked to a short form of our website, www.mb.org.nz.
When participants order tags, their details are added to the tagging database. After a butterfly ecloses and is ready to fly, a tag is carefully attached to its hindwing (see our how-to video here.). The tagger records details such as the weather and time of release on our website.
If a tagged butterfly is recovered, the finder enters the tag code, location, and site description into www.mb.org.nz, along with other relevant details like weather conditions. The journey of the butterfly is then shared with both the tagger and the reporter, and recorded in a database available for use by scientists, schools, and conservationists.
Join the Tagging Programme
Tags were available for $8.50 per sheet (25 tags) plus $2.30 postage per order but are now in limited supply for 2025 Autumn. Please email us to see if there are any available.
You can still help by watching out for tagged butterflies in your garden or community, helping us deepen our understanding of monarch butterflies in New Zealand and supporting their conservation. And telling everyone you know about it! If you can't tag this season, sign up for our free e-news to be kept informed or progress. Together, we can make a difference for these iconic insects!
Overwintering Sites
Do you know where monarch butterflies overwinter? Please report them to iNaturalist here.