Gorgeous Blue-Wren or Fairy-Wren

This small bird in a bright blue cap can be found in not dense undergrowth, and in meadows with scattered bushes, and in moderately dense forests, and in gardens. Superb Blue-wren adapt well to urban environments and are found in the suburbs of Sydney, Canberra and Melbourne.
Australian scientists randomly made an interesting discovery - the wren-fairy chicks must, before receiving food from their parent, sing a kind of password that they heard while still in the egg.

“This is a great example of prenatal learning that wren fairies use to distinguish their chicks from the parasitic cuckoo chicks that toss their eggs in other nests. We are sure that these birds ask for a password, and if the chick answers them, they feed him, and if not, he will not get food. "