Wrens: These Birds Can Identify Calls While Still in Their Eggs

Wrens : 

All discoveries aren’t intentional, some are made accidentally where researchers working to find one thing but stumble upon something unexpected. Well, this is one such accidental discovery.

Behavioral ecologist Diane Colombelli-Négrel has been studying Superb fairy wrens for over a decade.

When she was wiring the nests of wrens to record their sounds, she observed something unusual. Birds usually keep a low profile to avoid any predators’ attention, but female Fairy wrens sang while incubating their eggs in the nest.

“The discovery was a bit of an accident,” said Colombelli-Négrel, Flinders University, Adelaide, Australia.

Her discovery gave rise to the question – Could the baby birds be learning sounds, or perhaps even songs, even before they hatch?

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Ornithologists always wondered how prematurely in development can an individual learn to recognize distinct sounds.

In humans, offsprings begin recognizing the mother’s voice in the womb.

And in birds, the researchers believed that sound perception began only after hatching and perfected their song with parents.

But this belief started sliding down as the researchers began observing mother birds intentionally singing to their eggs.

Image credit: Maitlandmercury.Com.Au

“We knew we were on to something,” said avian ecologist Sonia Kleindorfer from Vienna University.

Kleindorfer, Colombelli-Négrel with their colleagues found that the unhatched superb fairy-wrens learned a distinctive vocal sound from their moms that helped mothers identify their own brood among others (invasive cuckoo).

This unique behavior isn’t only in Superb fairy wrens.

Researchers now have found at least 4 other species of birds that share these characters. The research report was published in the journal The Royal Society publishing’s Philosophical Transactions Of The Royal Society B.

It was a surprise to many researchers. “We used to think a lot of the learning happened after hatching, but now there seems to be more and more evidence suggesting, even in the embryonic stage… They are listening,” vocal learning neuroscientist Wan-Chun Liu from Colgate University said in a report.

A drop in heart rate of unhatched fairy-wrens when certain sound recordings of their own species played showed their attention to the stimulus. And when the sound of other species was played they showed no drop in the heart rate, suggesting they were responding to learn the vocal sound of their own species.

The team conducted the same four other species – Japanese Quail, Red-winged Fairywrens, Darwin’s small ground Finches, and Little Penguins to see if this phenomenon was among other birds. To their shock, all the birds and their eggs displayed the same phenomenon proving their result.

The team stated it will study even more bird species to uncover more secrets.