http://www.newsweek.com/baby-birds-start-learning-parents-calls-inside-egg-study-1628040

Just like babies in utero who get accustomed to their parents' voices from inside the womb, baby birds hear and absorb their parents' chirping and singing commands while waiting to hatch from eggs, according to Australian researchers.

That's the central finding of a study led by researchers led by Sonia Kleindorfer, a professor at the BirdLab of Flinders University in Adelaide, South Australia. Kleindorfer also heads the Konrad Lorenz Research Center at the University of Vienna.