It was difficult to miss the Blue Tiger migration through SEQ earlier this year. It made the news and went where few insect stories go, into social media and general public chit-chat. But where are they now and what were they doing here?

Blue Tigers are mostly a tropical butterfly and can be seen nearly all year round in North Queensland. They are migratory and fly south during spring and summer reaching southern Queensland, NSW and even Victoria. Huge numbers, probably in the hundreds of thousands, were seen widely across SEQ from November 2014 through to March 2015, with the highest abundance in January. If you stepped outside, they were impossible to miss.

This recent irruption of Blue Tigers was probably due to the high rainfall and hot temperatures in late 2014. These factors led to flush of new foliage on their main larvae host plant, Corky Milk Vine (Secamone elliptica) and the ability for lots of caterpillars to successfully pupate.

Corky Milk Vine contains several chemicals that are poisonous to many animals, but not to the Blue Tiger larvae. When the larvae eat Corky Milk Vine, the poisonous chemicals get passed on to the pupae and adult butterflies. These toxins then work to protect adult Blue Tigers from being eaten by birds, as birds have learnt that they get sick from ingesting Blue Tigers.

When cooler weather arrives, Blue Tigers will head back north passing through southern Queensland in April and May. They are known to congregate in huge numbers over winter, clustering on stems and vines in sheltered gullies in central and north Queensland. Individual Blue Tiger adults may live up to 6 months during which time they have migrated, bred and possibly over-wintered. Remarkable.

Despite there being a general migratory path of south in summer and north and autumn, Blue Tigers are often seen flying non-directionally or out to sea. There is still much to learn about butterfly migrations and invertebrate ecology in general, but the Blue Tiger migration is a welcomed spectacle of nature.

Article and photo by Deborah Metters

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25 responses on “The Blue Tiger Migration

  1. I was at Fraser Island for the last two weeks and saw large numbers of blue tigers, all flying North.
    Two days ago I counted the numbers flying past my camp site on a track on East Beach: 8 in first minute, 7 in second minute.
    At Caree, Northern tip of Island, they were being taken by Wood Swallows. I was trying to photograph the tigers and 5 were taken in as many minutes.

  2. Today i spotted hundreds, possibly thousands, of the blue tiger butterflies swarming around a species of paperback with yellow flowers, down by the Brisbane river, in a park with many of these trees , each filled with butterflies competing for necter. The stormy weather appeared to be encouraging them along a route leading to the east…. all that I witnessed seem to fly in the same direction. A Truly amazing sight.

  3. Huge numbers all heading north east over the last couple of days we are a 5 ks west of Noosa could they be heading for the coast turning left and following the coast line north?
    30 March 2020

  4. Blue Tigers are currently (3 April) flocking to Acronychia trees in Noosa National Park in large numbers

  5. The blue tiger butterflies have been migrating north along the Dune bush land and even along the open beach in large numbers since 27th March this year. We estimate at least 60 per minute.

  6. Burrum Heads April 2020. There were very large numbers of Blue Tiger butterflies around Burrum Heads over the last few weeks. Quite suddenly now, they have all gone. My Google search led me to this article which explains their sudden presence and disappearance. Thank you.

  7. Today 13/4/20 I saw a handful of These blue tiger butterflies flying north to north east out from bushland beach out to sea.

    The wind was quite strong, and noticed some others flying back in.

  8. Thousands heading north through Cudgen 2487 for past week I.e. 20th April 2020. Enjoying cleaner atmosphere due to Covid 19!,

  9. There are currently loads of them around the Sunshine Coast! They are especially prevalent on the beaches at Maroochydore, Mooloolaba and Alexandria Headlands. Such a beautiful site to see!

  10. Late August early September 2020
    Thousands witnessed in a gully 300m from the beach on North Stradbroke Island also showing considerable interest in flowering

  11. 14th November, 2020
    This morning, I discovered one of these lovely butterflies in the long milkweed behind our house at Speers Point, Lake Macquarie, NSW. I had never seen one before and went to the internet to check what it was. The blue grey underneath of its wings, the spotted head and body and the black and blue pattern on the top of its wings was mesmerising.

  12. I saw a blue tiger butterfly being fought by a common crow butterfly around a Peltophorum tree, along our front fence, first time for about 5 years. The last time I saw several blue tigers was under the shade of several Peltophorums, Ficus benjaminas and ironbarks, in our back yard about 400 metres away.

  13. Counted seven on Woolgoolga Headland (NSW) with about 5 other species, protected from a strong southerly. First time in thirty years that I’ve seen them here.

  14. I spotted some Blue Tigers today on the Lions Road, Qld side of the border. First time I’d seen one. I managed to get some nice photos of one on the grass.

  15. One visited me twice (or maybe two visited me once?) but it came right up to me then flew away & later, did it again. I’m in NSW Northern Rivers area, just near Lismore.

  16. Observed a number of Blue Tiger in North Haven, south of Port Macqurie, have lived here for the past 10 years and these are the first I have seen south of the Tweed

  17. Approx 30 years ago l was sailing up the queenland coast. Leaving cape townsend the northern point of shoalwater bay the sky was full of blue and white butterflys in their millions. They were heading in the same direction as me. I was heading one days sail to the percy islands. After about 6 hours into the trip they disapired. I anchored off south percy island and the next morning went for walk through a gully where some wild goats were feeding and in the trees were covered with the same butterflys.

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