What a mesmerising sight of colour and movement caught my eye when visiting an Auckland park this July – over 50 monarch butterflies dancing and feeding on the yellow flowers of the naturalised german ivy (Delairea odorata). The monarch butterfly (Danaus plexippus) is New Zealand’s most identifiable butterfly. We consider it a native because it was self-introduced in 1870s having ‘island hopped’ from North America. Not only that it is dependent on the introduced swan plant (also known as milkweed) for survival.
Differences in migration in New Zealand
Monarchs here do not follow the same migration pattern as their northern relatives where they can travel up to 9,000 km to winter over in Mexico. This incredible migration has recently been disrupted through climate change and loss of habitat.
A captivating read about monarchs and migration is beautifully portrayed in Barbara Kingsolver’s recent novel Flight Behaviour
Lifespan according to season
New Zealand monarch’s have adapted their migration behaviour to suit local conditions. When the air temperature drops to 12.8°C, monarchs flock together in overwintering sites. These sites tend to be in milder coastal locations where the temperature remains at least 10°C. The generation of monarchs that are born in autumn don’t mate till spring and live longer (6-9 months) than previous generations which live between 4-6 weeks.
Where to find monarchs wintering over in NZ
Overwintering monarchs prefer sites that are sheltered from the wind, have trees with a rough bark surface on which to cling and have a nearby source of nectar. The butterflies are mostly inactive, but on warm days, they fly, bask in the sunlight and feed on nectar as I witnessed here in Auckland
Swarms form regularly to overwinter at places such as Tauranga Bay in Northland. The Monarch Butterfly New Zealand Trust (MBNZT) http://www.monarch.org.nz/monarch/ was initially formed to protect this site. Other overwintering sites include areas of Hawke’s Bay, Nelson and Christchurch. See this resource for where to find them in Christchurch http://resources.ccc.govt.nz/files/MonarchButterflies-environmentecology.pdf
When the temperatures warm up, butterflies move inland to reproduce.
Protection from predators
Monarchs use bright colours and the toxicity from their larval swan plant food source as defence mechanisms. This is enough to keep vertebrate predators away, with the exception of the shining cuckoo.
Male female difference
Males are a bit bigger than female monarchs and have a spot known as the androconium in the middle of each rear wing. Wings of females boast of darker veins.
Finding a resting site of hundreds of monarchs is such a ‘wow’ experience – the vibrant colours, the beauty and grace and a chance to study them closely as they rest up ready for the next stage in their cycle.
My wife fern raised over 300 monarchs last year this year we added a second shade house and shes aiming at 500 from about 250 swan plants we live in Auckland.
YAY Well done you – we are going to plant more this year too
Hi Bill and people of Auckland. I’ve currently got one swan plant (in a pot) with at least 10 caterpillars on it. They need a new home that has plenty of swan parts to sustain them. Can anyone help? Central, west and north locations preferred. Thanks
Hopefully someone picks up your request and offers a home for your caterpillars. Sorry I can’t help – I live in Christchurch. Alternatively maybe a nursery near you is selling swan plants and you could grab one and transfer the caterpillars over. All the best.
Wee took in the last 4 surviving caterpillars from our swan plants when the weather turned bad here in Christchurch. We put them n a shoe box and sure enough they all formed chrysilises (?) and now the first one has pupated and is hanging around in our living room. I have put out an eggcup of honey water for nectar and am hoping that they may spend the winter here until the spring comes. Is my hope real or misplaced do you think?
Exciting to have your own Monarchs. What you have been feeding the Monarchs sounds fine but could do with more variety. The best place to get your questions answered is the Monarch Butterfly New Zealand Trust web page that has a section called Frequently Asked Questions https://www.monarch.org.nz/faq/. The answer to what Monarchs feed on is on that page and would be worthwhile reading. This is taken from that page
“Adult butterflies need plants giving nectar. They usually choose flowers with bright colours, purples, pinks and blues in mass plantings. Buddleias and Hebes are very popular. There are more listed in our forum – click on the link on the homepage to go there. There is a poster showing many nectar plants available from the MBNZT.” All the best with caring for your Monarchs over winter
Hi what is the plant called the monarchs feed on during the winter i have 1 of a group of 6 that have hatched the others have been set free a couple of weeks ago its getting quite cold now and being in the lower north island its not warm out side so i have her inside and ive ben giving her clear fruit juice . syrup plus a mixture of honey water and a drop od soy sauce plus some water also i may keep her over the winter inside so just wondering what else to feed her ,thats why i asked what the plantis they feed on over winter ,i have heebes but they have long sice finished flowering i took her out side yesterday in the sun but she is quite happy to say with me .
What you have been feeding the Monarchs sounds fine. The best place to get your questions answered is the Monarch Butterfly New Zealand Trust web page that has a section called Frequently Asked Questions https://www.monarch.org.nz/faq/. The answer to what Monarchs feed on is on that page. This is taken from that page
“Adult butterflies need plants giving nectar. They usually choose flowers with bright colours, purples, pinks and blues in mass plantings. Buddleias and Hebes are very popular. There are more listed in our forum – click on the link on the homepage to go there. There is a poster showing many nectar plants available from the MBNZT.” All the best with this!
We have recently published on our website a list of known overwintering sites for monarch butterflies in New Zealand, after 13 years of capturing data. You can see the full list here:
We are also keen to hear of other sightings which can be noted on our site http://www.mb.org.nz.
Huge thanks for the link – this will be invaluable information to those keen to see the monnachs
I had a swan plant in New Plymouth on which grew 3 large caterpillars until they devoured the whole plant. I get them on pumpkin for a couple of weeks until they disappeared. Several weeks later I noticed a Monarch butterfly on a rosemary plant near to where I had the swan plant. It has stayed there for 2 days.I would like to think it was one of my “babies” I looked after!
Hi Sue, I have read on the Monarch website where pumpkin is not good for them it might pay you to check it out
Its really annoying, I have a small dark green swan plant that has 2 FAT caterpillars on it and its almost stripped bare, so I have relocated some potted swans next to them so they can transfer over when they’re ready, but over in the corner of my section is a huge clump of large swans with lighter coloured leaves with not a single thing on them,
I found a monarch on my rosemary in Sth Wairarapa yesterday, I was surprised it survived the storm we had the previous two days.