Cuckoos Can’t Copy This: Fairywren Egg-to-Chick “Code”

Added: 2026-05-25

[00:00:00]Before the egg hatches, the mother presses close and sings the same note over and over. The embryo inside listens, learns. When it breaks through the shell, its first begging call contains that note.

[00:00:14]The parents will not feed a chick that gets it wrong.

[00:00:17]Cuckoos cannot learn it in time.

[00:00:19]In Australia, this is the superb fairy-wren.