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Tagging Monarchs

Our tagging programme was established to determine any migration patterns within the NZ monarch population. Based on the analysed data there appeared to be no pattern of migration or any common destination. Most recoveries were made within the general area in which they were released.

With the formation of the MBNZT, tagging of monarchs in New Zealand began in 2005-06 as a trial. From 2007 widespread tagging took place for thirteen years.

Each tag had a discrete “code number” prefixed by two or three letters which related to a particular year (e.g. T series = 2020) The tags linked to a short form of our website,


When participants ordered tags, their postal details were recorded on the tagging database online. As they released their butterflies, they would enter other information such as the weather, time of day etc.

When a tagged butterfly was recovered, the person would go to and enter the number from the tag there along with the postal location of where it was recovered, a description of the site and other important information as to weather etc. When they finished entering the data automatic responses were triggered which went out to the tagger, the person who reported it, and the administrators of the project. The information was also recorded in a database.

Tagged monarch Cosima Ray for IG (2021_03_01 11_21_31 UTC)

Anecdotal records, plus the tagging data, indicated that most monarchs overwintered in the area around where they eclosed.

During 2024 we plan to identify the overwintering sites (some are already known) and encourage volunteers living in the vicinity monitor the populations. It is assumed that these populations go into diapause. A methodology is to be established 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.

Tagging Results


Click here for information about tagged monarchs in Australia: Australia.

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