Blue Water Dreaming
Nature Surprises - From Mackay to Gloucester with the butterflies
Butterflies set out to sea
Thousands of butterflies along the way from Mackay to Thomas Island
When leaving Mackay in early May 2015, I was surprised to see hundreds of butterflies flying out to sea, apparently to nowhere. A beautiful butterfly would fly over our heads and just keep going, as soon as it disappeared in the distance, another one would come and disappear in the same direction. There seemed to be an unlimited supply of butterflies out to sea.

I was so amazed at this sighting that later on did some research and find out that butterflies, like birds, do migrate to warmer temperatures when winter approaches. There are many varieties and some like the Monarchs (also called Wanderers) will travel long distances from Canada to Mexico covering hundreds of miles during their lifecycle.
Our butterflies were the Blue Tiger variety and as it turned out that year of 2015, testimonies of large number of Blue Tigers in Brisbane were reported. It is believed that high rainfall and hot temperatures in late 2014 produced large numbers of butterflies that then migrated north to warmer latitudes, a bit like we’ve been doing lately every year after cyclone season. 
Blue Tiger Butterfly
Despite there being a general migratory path of south in summer and north in autumn, Blue Tigers are often seen flying non-directionally or out to sea.
Some more reading led me to discover that butterflies in this group are the longest lived of all species. They feed mostly on toxic plants, fly slowly and spend long periods resting in sheltered areas during winter. The toxins they eat work to protect the adults from being eaten by birds, as birds have learnt that they get sick from ingesting Blue Tigers. They are mostly tropical and can be seen year round in North Queensland.
No matter what the explanation of this migratory behavior is, it was a remarkable spectacle anywhere we looked little butterflies around us in the middle of the sea.
Cape Gloucester - Eco Resort
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
About a week later when we arrived in Cape Gloucester they had beaten us there, hundreds of them sucking food from the trees.