Parents sometimes “speak” to the fetus in the mother’s womb, and when they’re born, they almost always sing a gentle lullaby to help put them to sleep. But female birds? Do they communicate with their chicks while they’re in the shell?
Researchers at the University of Vienna (Austria) and Flinders University (South Australia) have found that in the low-grassland swaying nests of Australian songbirds, the mother birds take “singing” to even greater heights.
Bird ecologists from around the world have shown that a native wren mother’s signature call to her eggs helps to give her newborn their distinctive call for food – helping these fairywren species to bond with and prepare their young for the real world.
Wrens teach their young even before their chicks hatch
By calling to them in the egg, the new study published in The American Naturalist under the title “Nestling begging calls resemble maternal vocal signatures when mothers call slowly to embryos” found that the nestlings responded favorably to the mother’s ‘B element’ vocalization.
The special individual calls by fairywrens (Malarus cyaneus) appear to “teach” their unborn chick’s distinct call type both inside the egg and emerging into the nest, said Flinders and University of Vienna Prof. Sonia Kleindorfer, an organismal systems biologist with a research focus on how animal behavior shapes evolutionary dynamics in birds and parasites founded the Flinders University BirdLab two decades ago.
The study of fairywrens was conducted by Flinders University scientists in South Australia at the Cleland Conservation Park. “In eight species of fairywren and grasswren, females produce a B element to their embryos that is the mother's signature element and unique to each female.
“This B element is also the nestling begging call produced shortly after hatching,” she said.
“In this study, we show that female songbird mothers produce a vocal signature element to their embryos that is later produced by their nestlings as a begging call. Nestlings produce calls with greater vocal copy similarity between their mother's signature call and their begging call when mothers called slowly to the embryo.”
Female bird's vocalization behaviors
Kleindorfer and her colleague Dr. Diane Colombelli-Négrel said extended studies by the BirdLab research are giving new insights into the extraordinary female vocalization behavior of Australian songbirds that has long been overlooked. “Nestling begging calls resemble maternal vocal signatures when mothers call slowly to embryos,” noted Colombelli-Négrel.
“In this study, we show maternal behavior that is concordant with pupil-directed vocalization behavior when mothers call to their embryos. Mothers with a slow call rate had offspring with enhanced learning (greater vocal copy similarity) of a vocalization experienced in the egg.” In each species, other element types in addition to the B element were also produced by mothers calling to their embryos.