Zelda Ocarina of Time, what does it mean when Navi changes colour?

Answer 1

i'll assume when she turns green, is what you're asking

that means that there's something that can be done there

perhaps you can play your ocarina and something will happen..

chances are that its' the scarecrow song you'll need, and if you didn't write a scarecrow song in your game then nothing will happen.

go to lake hylia, and play something on the ocarina near the scarecrow - he'll tell you what to do next

Answer 2

it means you have to play a certain song