This is bird note.

Shorebird chicks hatch into a dangerous world.

Larger birds would love to turn them into a snack.

So they need to be vigilant from the start, emerging with eyes open and

walking within a few hours. And scientists are learning that some species may be

aware of the outside world while still inside the egg.

Researchers in Australia studying masked lap wings and red-capped plovers,

two species of shorebirds, notice the chicks began chirping in their final days in the egg.

They wondered if the chicks would fall silent if their parents left and a predator appeared.

They played a recording of little ravens, which hunt for young birds, over the eggs a few days from hatching.

The shorebird embryos made fewer chirps during the Raven recording,

while adult shorebird alarm calls and white noise had no effect.

The finding suggests the chicks are listening carefully and may be able to tell

threatening sounds from non-threatening ones. It's still unknown just how much unhatched birds can learn.

Birds as different as goals, griebs, and turns start chirping before they hatch.

Future research could reveal just how alert these precocious chicks are within the egg.

For bird note, I'm Ariana Rimmel.