Fairywrens learn calls before hatching
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New research demonstrates that some songbirds start learning to imitate their parents' vocalisations before they even hatch.
Many birds learn their songs from their parents and vocal learning has many benefits for birds: it lets them signal their suitability as a potential mate, recognise their relatives and flock members, and enhances social interactions in many ways.
Once Diane Colombelli-Négrel and Sonia Kleindorfer of Australia’s Flinders University, Mark Hauber of New York City’s Hunter College and their colleagues from Cornell University discovered that Superb Fairywren nestlings learn to imitate their mothers’ calls while still in the egg, they wanted to see whether this behaviour extended to other species and to learn more about its ecological context. They turned to the related Red-backed Fairywren.
All Red-backed Fairywren females in the study called to their eggs while incubating, and most continued to call to their nestlings for five to six days after they hatched; as a result, mother and offspring calls were more similar than would be expected by chance. Parents also put more effort into feeding nestlings with calls similar to their own. “Fairywrens have become a new model system in which to test dimensions in the ontogeny of parent-offspring communication in vertebrates,” said Hauber.
Though the researchers had hypothesised that fairywren parents could use calls to identify alien nestlings, the result of eggs placed in their nests by parasitic cuckoos, the rate at which Red-backed Fairywren mothers called to their eggs did not increase significantly when more cuckoos were present in the habitat. Colombelli-Négrel and colleagues speculate that the similarity of nestlings’ calls to their own could also tip parents off about which nestlings are the most vigorous and the best learners, so that they can invest more resources in the ones most likely to survive.
The original discovery was a fortuitous accident. “Because fairywrens have high predation rates, we originally placed microphones under Superb Fairywren nests to record alarm calls against predators twenty-four seven,” says Colombelli-Négrel. “As a result, we discovered embryonic learning in Superb Fairywrens.”
When they turned to Red-backed Fairywrens, they recorded vocalisations from 67 nests across four breeding seasons in Queensland, Australia, as well as playing recordings of begging nestlings to test parents’ responses.
“Prenatal vocal learning has rarely been described in any animal, with the exception of humans and Australian Superb Fairywrens,” said Dr William Feeney of the University of Queensland, an expert on the interactions between cuckoos and host birds. “In this study, the authors present data suggesting that, like the Superb Fairywren, Red-backed Fairywrens also learn their begging calls from their mother. This result is exciting as it opens the door to investigating the taxonomic diversity of this ability, which could provide insights into why it evolves.”
Reference
Colombelli-Negrel, D, Webster, M S, Dowling, J L, Hauber, M E, and Kleindorfer, S. 2016. Vocal imitation of mother’s calls by begging Red-backed Fairywren nestlings increases parental provisioning. The Auk: Ornithological Advances 133: 273-285.
Many birds learn their songs from their parents and vocal learning has many benefits for birds: it lets them signal their suitability as a potential mate, recognise their relatives and flock members, and enhances social interactions in many ways.
Once Diane Colombelli-Négrel and Sonia Kleindorfer of Australia’s Flinders University, Mark Hauber of New York City’s Hunter College and their colleagues from Cornell University discovered that Superb Fairywren nestlings learn to imitate their mothers’ calls while still in the egg, they wanted to see whether this behaviour extended to other species and to learn more about its ecological context. They turned to the related Red-backed Fairywren.
All Red-backed Fairywren females in the study called to their eggs while incubating, and most continued to call to their nestlings for five to six days after they hatched; as a result, mother and offspring calls were more similar than would be expected by chance. Parents also put more effort into feeding nestlings with calls similar to their own. “Fairywrens have become a new model system in which to test dimensions in the ontogeny of parent-offspring communication in vertebrates,” said Hauber.
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| The female Red-backed Fairywren appears to teach the unhatched nestlings to vocalise while incubating them. Photo: Colombelli-Negrel. |
Though the researchers had hypothesised that fairywren parents could use calls to identify alien nestlings, the result of eggs placed in their nests by parasitic cuckoos, the rate at which Red-backed Fairywren mothers called to their eggs did not increase significantly when more cuckoos were present in the habitat. Colombelli-Négrel and colleagues speculate that the similarity of nestlings’ calls to their own could also tip parents off about which nestlings are the most vigorous and the best learners, so that they can invest more resources in the ones most likely to survive.
The original discovery was a fortuitous accident. “Because fairywrens have high predation rates, we originally placed microphones under Superb Fairywren nests to record alarm calls against predators twenty-four seven,” says Colombelli-Négrel. “As a result, we discovered embryonic learning in Superb Fairywrens.”
When they turned to Red-backed Fairywrens, they recorded vocalisations from 67 nests across four breeding seasons in Queensland, Australia, as well as playing recordings of begging nestlings to test parents’ responses.
“Prenatal vocal learning has rarely been described in any animal, with the exception of humans and Australian Superb Fairywrens,” said Dr William Feeney of the University of Queensland, an expert on the interactions between cuckoos and host birds. “In this study, the authors present data suggesting that, like the Superb Fairywren, Red-backed Fairywrens also learn their begging calls from their mother. This result is exciting as it opens the door to investigating the taxonomic diversity of this ability, which could provide insights into why it evolves.”
Reference
Colombelli-Negrel, D, Webster, M S, Dowling, J L, Hauber, M E, and Kleindorfer, S. 2016. Vocal imitation of mother’s calls by begging Red-backed Fairywren nestlings increases parental provisioning. The Auk: Ornithological Advances 133: 273-285.
