In the trees, the birds have learned to speak every color.

16 seconds sound clip from the The Last Unicorn movie soundboard.

You can hear this line at 00:56:49.618 in the Blu-ray version of the movie.

Quote context

[...]

- Please, lady, let me help you. What can I do for you? Trust me!

- In the sea, the fish have learned to fly, on a moonlit night, on wings of silver, as the enchanted stars sail serenely by.

- Do they know where do unicorns go? Where winged horses fly?

- North Wales lost at sea and never seen again.

- Go, go and ask the magpie, 'Where do unicorns go?'

- In the trees, the birds have learned to speak every color.

- They keep their secret in a parade of clouds, playing hide and seek.

- Do they know where do unicorns go? Where winged horses fly? (2)

- North Wales lost at sea and never seen again. (2)

- Does myth and mystery lie where the unicorns go?

[...]