By Pat Leonard
June 9, 2016
Rather like an expectant human mother playing Mozart to her unborn child, some mother fairywrens call softly to their eggs. Now, two recent studies conclude that two species of fairywrens can hear their mothers and even learn elements of her calls while still inside the egg.
Imitating their mother’s calls may ensure they are fed as nestlings, helping to distinguish them from the cuckoo nestlings that sometimes show up in nests. Retaining key elements of her call throughout their lives may also serve as a family “password” long after the young have grown and are raising chicks of their own.
Fairywrens are small Australian songbirds. Nine species occur on the continent where they can be common suburban birds, in places as familiar as chickadees are in the U.S. The males are often brilliantly colored in glittering blue or red, and the species’ unusual breeding habits have made their behavior a popular research topic for decades.
A series of experiments on Superb Fairywrens led by Diane Colombelli-Négrel and Sonia Kleindorfer of Australia’s Flinders University suggested the embryos were learning while still in the egg—contradicting a long-held view that embryos have limited learning abilities. Even among humans, it’s only been in the past few years that research has shown an unborn baby can begin to learn the sounds of speech when it is 30 weeks old.