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Birdsong warning helps unborn chicks beat the heat, study finds
Media release
16 June 2026
Researchers from Deakin University, led by Visitor Dr Mylene Mariette, have uncovered a remarkable survival strategy in one of Australia’s most familiar birds — the zebra finch — showing that even before they hatch, chicks can be “warned” about hot weather and begin preparing their brains to cope.
Recently published in the Journal of Experimental Biology the study is a collaboration with scientists from the United States and reveals that zebra finch embryos inside the egg respond to a special heat-related call made by their parents.
This sound — only used during hot conditions — triggers changes in how the chicks’ brains develop, potentially helping them better handle extreme temperatures later in life.
Behavioural ecologist Dr Mariette says the findings highlight just how powerful sound can be — even before birth.
‘It’s extraordinary that just hearing a sound inside the egg can change how the brain develops,’ she said. ‘These birds may be preparing their young for a hotter world before they’ve even hatched.’
To test the idea, researchers collected freshly laid zebra finch eggs and incubated them under optimal temperature. Some eggs were played recordings of the parents’ “heat call,” while others heard different, normal parental sounds.
Just before the chicks were due to hatch, scientists examined their brains to see which genes were switched on or off. Embryos exposed to the heat warning changed the activity of genes linked to blood flow and fluid regulation — key processes that help cool and protect the brain.
‘This suggests the brain may be getting ready to protect itself from heat stress,’ said Dr Mariette.
Zebra finches are native to Australia. Over the past decade, Dr Mariette’s work at Deakin has shown that these birds use specialised calls to help their offspring prepare for heat, influencing behaviour, growth and physiology.
This is the first study to pinpoint what is happening in the brain itself.
Initially, the research team expected to find changes in genes linked to hormones, stress and temperature control, based on the impact of heat calls they had previously observed on nestlings growing in the heat. Instead, the strongest effects were seen in genes controlling blood vessels and the flow of fluid around the brain. These changes could make the brain’s protective barrier more flexible, an important feature for coping with high temperatures.
‘That these genes in particular responded is amazing, we didn’t know it was possible.’
Importantly, the embryos in this experiment were never exposed to high temperatures, only to the sound of their parents calling in the heat. Yet their brain development still shifted in the same way as if they had experienced heat directly.
‘That both heat and the sound of heat produce similar effects is fascinating,’ Dr Mariette said. ‘It shows how finely tuned these birds are to their environment, but we now need to understand what this means for their ability to cope with extreme heat.’
While the findings suggest such brain changes could help protect birds from heat stress - or even heatstroke - researchers say more work is needed to confirm the direct benefits.
As climate change drives more frequent and intense heat events, understanding how animals adapt — especially at such an early stage of life — is becoming increasingly important.