Why are thousands of butterflies on the Northern Rivers?
THERE'S a bright side to the weather phenomenon that has created a dry spring for the Northern Rivers and a wet one west of the Great Dividing Range.
Senior curator of entomology at the Queensland Museum, Chris Burwell, said high rainfall and increased temperatures out west meant the butterflies had a very successful breeding season and they were now in search for food.
"No one has all the answers, but (the mass migration) probably has to do with the fact that because they bred in huge numbers, they've eaten their particular food source bare and are probably moving on in search for more," he said.
Gold Coast Butterflies organiser Josephine Romeo told the Gold Coast Bulletin the butterflies were likely pushed towards the coast instead of further north due to north westerly winds.
Dominant westerly winds are the result of a weather event in place right now called the Negative Indian Ocean Dipole.
Dr Burwell said the butterflies were known to undergo unpredictable, mass movements.
"We're calling them migrations in the sense they are moving from one place or another ... it's not like a regular migration where they move on way in winter and back the same way in summer," he said.
"The direction they head and when is unpredictable."
He explained butterflies sometimes ended up south or even out at sea due to wind, where they would hit deadends looking for food sources.
The butterflies out-and-about are the caper white and the meadow argus butterflies.
The caper white butterfly is white and black (pictured) and the meadow argus is brown with orange patterns.
Dr Burwell said those looking to photograph them or watch them should head out in the evening and search around flowering plants.
Some media outlets reported that a huge migration of butterflies such as this might only happen every six to 10 years.