This is bird note.

The asteroid that struck the Yucatan 66 million years ago

wreaked worldwide ecological damage.

It spelled the end of most dinosaurs and other animals and

destroyed the world's forests. Yet a few bird-like dinosaur groups made it through.

Scientists believe all those groups were ground dwellers.

Most could fly, but being largely terrestrial

was a key survival advantage in the absence of trees.

This means that of the 11,000 species of birds that fly the skies,

glide over the oceans, and flit among the branches today, all descended from those

ancient ground-dwelling bird-like creatures. The mass extinction utterly changed life on earth.

But as one world ended, another unfolded.

A great deal of the world's present diversity of life emerged following the catastrophic events of 66 million years ago.

And many different groups of birds evolved to reclaim a life in the trees. The birds around us today are living proof of nature's resiliency.

For Bird Note, I'm Michael Stein.