Baby birds can learn sounds before birth

A new study led by the BirdLab research group at Flinders University discovered evidence of prenatal auditory learning in embryos of five bird species. Using non-invasive techniques, researchers found fluctuations in heartbeat responses to their parents’ calls in the embryos of three vocal learning species (the superb fairy-wren, the red-winged fairy-wren, and Darwin’s small ground finch), as well as two vocal non-learning species (the little penguin and the Japanese quail).

“By studying the capacity for sound learning in embryos, we are paving the way to new inroads into evolutionary and developmental timescales,” said study first author Dr. Diane Colombelli-Négrel. “Long before actual vocalization, we found that these tiny songbirds were also discriminating towards non-specific sounds and capable of ‘non-associative’ (not from parents) sounds, building on the complexity of vocal learning in songbirds.”  

According to study co-author Professor Sonia Kleindorfer, vocal production learning is believed to occur in just seven lineages of birds and mammals: songbirds, hummingbirds, parrots, cetaceans, pinnipeds, bats, and, among primates, only humans. 

“As a result of the rarity of vocal production learning, animals have been grouped into so-called ‘vocal learners’ (those that learn to imitate a vocalisation from a vocal tutor) and ‘vocal non-learners’ (animals that produce vocalisations without imitating a vocal tutor),” explained Professor Kleindorfer.

Surprisingly though, this new study found that embryos could grow accustomed to another bird’s call in both vocal learning and non-learning species, and may thus point to a phenomenon more widespread than initially thought.

“This research will hopefully inspire more study into the remarkable capacity of animals to learn sound,” said Professor Kleindorfer. “By moving the time window for sound learning to the prenatal stage, this research direction opens pathways to measure neurobiological downstream effects of early auditory experience on behaviour and information processing.”

The research is published in the journal Philosophical Transactions of the Royal Society B.

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By Andrei Ionescu, Earth.com Staff Writer