The North Island Monarch corridor

This topic contains 5 replies, has 4 voices, and was last updated by  Jacqui 5 months, 2 weeks ago.

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  • #54771


    Kia ora friends!

    I read the last issue of the MBNZT magazine (#26) with much interest. My favourite article was on page 12, in particular the lower left corner image that showed the distance travelled by a monarch from Pukawa Bay near Turangi, all the way up to Mairtown near Whangarei.

    It got me thinking about the possibility of there being a “Monarch Corridor” that goes through the central plateau, which is favoured by monarchs to travel up an down the country.

    I started noticing eggs on my milkweeds in about October (I’m in Taupō). They were very few, and even though I never actually saw monarchs at the time, it was clear they were about. Of those handful of eggs, two caterpillars made it to chrysalis stage (one of them is still ‘green’). One healthy male eclosed just a few days before Christmas.

    I tell it in a bit more detail on Twitter:

    I also noticed that in 2018 a lot of people were complaining about not sighting monarchs, whereas others were getting quite a few eggs and caterpillars.

    I don’t know if anyone has thought of or done this before, but an interesting research project would be to collect information from people about three things:

    1- number of eggs per swan plant (I know it sounds daunting, but with patience and dedication this can be achieved!)
    2- date of when you saw the 1st egg
    3- your location within New Zealand

    Other useful information can also be added, like what size is your milkweed patch, when did you establish it, date when you first noticed 1st instar bite marks on the leaves of your plants, etc.

    We can then create a chronological monarch egg ‘heat map’ of NZ. It would be a dynamic map, where (especially at the start of the monarch season) a pattern of migration could be detected as areas that get eggs first get ‘hot’ sooner, and other areas of NZ catch up as the monarchs migrate.

    What do you guys think?

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  • #54853


    Hi Vanda

    I did have some eggs in September but very few this year. And I needed hundreds of butterflies for the show – fortunately others contributed. Some came from Waipu, a huge amount in fact.



    So what do you think of the possibility of monarchs coming across the Cook Strait? Maybe blown in a southerly although its hard to imagine how they would survive that … don’t know. I’m in Welly and I’ve always assumed the first butterflys for the season have overwintered here. My last release last season was on Matariki … a female. And I’ve fondly thought it was that female that came back to lay eggs in September this year. There is so much bush and isolated wilderness around Wellington I’m sure there must be overwintering sites I don’t know of. It would be interesting to know how far they travel.



    I have released 200+ Monarchs per season for the last couple of years, & I note that there have been a few over-wintering Monarchs in Dominion Park, Nawton, Hamilton for the last couple of years. We often wonder if they are some of ‘ours.’ No I haven’t tagged any, my hands are a bit shaky; I;m not in the first flush of youth. I try to ensure that the first eggs of the season & the last ones especially have a good chance of making it through to adult butterflies by bringing them inside.



    7 butterflies in October! That means you must’ve had your first eggs in September (or even late August as temperatures were cooler). It’d be really interesting to know where those very early butterflies that laid the eggs came from.

    I first noticed eggs on my milkweeds around mid October (that’s roughly 4 weeka after you).

    I also recall Jacqui saying that she had to have eggs sent to her from other parts of the country in preparation for the NZ flower and garden show in Auckland that happened in late November.

    So if Hamilton had eggs in September, Taupō had eggs in October, but Auckland had no eggs prior to November, it seems plausible to assume that our monarchs flew from the south as opposed from their overwintering location in Northland.

    By the way, do you tag your butterflies? I’m really thinking about doing that this season. 😊



    That sounds a great idea. I’m in Hamilton & have plenty of swan plants, some in a netted enclosure which I keep as food for ‘captive’ caterpillars, & some in the general garden where the Monarchs can freely lay their eggs.
    I released 7 butterflies in October, all raised from eggs. I released 52 butterflies in November.
    But only 7 in December. Tho I have quite a few cats in all stages in my ‘hatchery’ -in the conservatory.

    At the moment there are plenty of butterflies in my garden, every day, but eggs seem to be being predated. Also, we had a lot of rain in early December, & I wonder if some of the eggs failed to ‘stick’ to the leaves. At one stage I very carefully brought in 5 leaves each with an egg on them, but when I got inside, only 3 eggs were in evidence!

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