With squadrons of butterflies gracing Mackay this week, locals could be forgiven for thinking there’d been a major hatching event.

But the creatures are winter survivors that toughed out the cooler, dryer months and are now emerging with warmer weather.

Senior curator of entomology at the Queensland Museum Dr Chris Burwell said the butterflies were likely an echo of a breeding frenzy earlier in the year.

“Butterfly numbers just exploded all throughout eastern Queensland all the way down to Brisbane,” Burwell said.

“A lot of those butterflies, that were flying around, just die off as it starts to cool down as you start to hit winter.

“[But some] spend that cool dry period in shady gullies, where there’s a bit of forest along the watercourses, a bit of rainforest or vine scrub.”

‘Very good breeding conditions’

Just as Australia was about to introduce its first coronavirus restrictions back in March, Queensland experienced an abundance of butterflies.

“We had a really good end to autumn, where we had some really good rain in February,” Burwell said.

“Because we had those really good rains towards the end of summer … and quite a warm autumn that prolonged for quite a long time, breeding conditions were still very good.”

The situation is being replicated at Glenagra Station, near Kynuna in outback Queensland, where you could be forgiven for thinking you were in a butterfly museum exhibit.

The cattle property is cared for by farmsitters Neil and Linda Zoglauer who have been there for six years.

Mr Zoglauer said when spring comes the butterflies do as well.

“I was starting one of the bores up and I just noticed, I saw something flying up from in the grass,” he said.

“Some had hatched, there were some hatching, and I thought I’d try to capture what I could of them.

“There was quite a lot on that particular bush — they’d nearly demolished all the leaves on it.

Burwell said the large numbers meant more butterflies had survived the winter.

“They aggregate in shady spots, sometimes in tens of thousands,” he said.

“Those aggregations of thousands of butterflies are now starting to disperse and fly away from those resting places to breed up and start the cycle again.”

He said it was a common phenomenon experienced every year.

“I think the reason why it’s a little bit more obvious this year is because we had such a large production of adult butterflies,” Burwell said.

He said the same flurry of butterflies emerging from winter hadn’t been experienced in Brisbane yet.

“Maybe it’s a little bit easier to overwinter the further north you go, hopefully we’ll start seeing some large numbers of these things turning up in Brisbane again,” Dr Burwell said.

Burwell said it was a great opportunity for Mackay to enjoy the creatures.

“Whether that will translate to big numbers say over into next year is hard to tell, it will depend on what rains we get as spring and summer progress,” he said.

– ABC / Ollie Wykeham and Angel Parsons