Be a butterfly citizen scientist!

May 2025

If you are in New Zealand, keep an eye open for tagged monarchs during the cool months. These are butterflies with with stickers on their wings with a code on them. If you see a live tagged monarch or find a dead one, take a photo of the tag if you can and then logon to the Moths and Butterflies of New Zealand (MBNZT) to enter it into their project database, along with its location and the conditions.

A previous New Zealand survey using tags showed the vast majority of monarchs did not migrate like their East Coast US counterparts. The current project is trying to identify where monarchs go to overwinter and over 4000 butterflies have been tagged across the country. In some areas, like Nelson and Christchurch, the overwintering sites are quite well known by local butterfly enthusiasts. In other areas, such as Auckland and Northland, very little is known about where the butterflies go to see out the bad weather until they can reproduce. This may be because it is still warm enough for them to breed and they do not congregate for long periods of time, unlike the South Island, where the groups of monarchs in local parks can be spectacular. I couldn't find any details of even historic overwintering sites on the North Shore, but they must be around somewhere because I'd always see one or two on sunny winter days at the old house in Hillcrest.

Monarchs are known to congregate in tall trees like macrocarpa, pohutukawa, silky oaks and conifers, on their northern sides to maximise the sun. MBNZT also have an iNaturalist project to record overwintering sites, another good reason to sign up for an account if you haven't already. It is thought butterflies can identify safe roosts from scent left in previous years.

The current known Auckland overwintering sites are Blockhouse Bay Recreation Reserve and Jellicoe Park in Onehunga (although none have yet been seen there in 2025). There must be more overwintering sites around so be a butterfly citizen scientist and keep your eyes open the next time you are out in the bush or park. The butterflies can look like a bunch of dead leaves at first sight (clever things), so they might not be as obvious as you would expect. And if one has a tag, you now know what to do!