Female superb fairy wrens (Malurus cyaneus) in Australia sing to their eggs for a quite specific reason, to teach the embryos a single unique note that is a “password.” The hatchlings must incorporate this special password into their begging calls in order to get fed.
The reason for this prenatal instruction? So the wrens can identify their own offspring from those of two cuckoo species who are considered “brood parasites” because they routinely lay their eggs in other birds’ — in the wrens’ — nest. As researchers write, the “cost of making a recognition error is high” for these avian parents.
Read more: http://www.care2.com/causes/wrens-teach-their-eggs-to-sing-a-password.html#ixzz2CsuDF9UY