Friday, 16 November 2012

Superb Fairy-Wrens learn in ovo

Just had an email from the British Trust for Ornithology which included this link to a fascinating article about Australian Fairy-Wrens.  Apparently, as a defence against cuckoos, Superb Fairy-Wren females sing to their eggs, and what they sing includes a nest-specific key call which the young, having hatched, have to repeat back to the parents before the parents will feed them.

Researchers were recording near the birds' nests to see if they could record any anti-predator calls, but what they got was the mothers singing to their eggs.  They determined that the key call was nest-specific by swapping batches of eggs between nests.  The embryos learned the key call from the foster mother, showing that it was not inherited from the parents and must have been learned in the egg.

The young have about 5 days before they hatch to learn the key, while cuckoo embryos, because the eggs are laid later, have only two days.  It's a clever strategy, but still only works about 40% of the time, as the cuckoo chicks try out various different calls in the hope of striking lucky, which presumably they do much of the time.

No comments: