The flute isn't really a regular flute - it is a romanian instrument called "tilinca". The structure is like of the flutes(with a whistle blower) but there are no holes to play on. The only hole is through the flute(it's elderberry so it has this sponge like core it is easy to get it out). So when you sing you just have to blow the whistle and control the notes by just putting you finger at the other hand. The harder you blow the higher it sounds.
http://www.eliznik.org.uk/RomaniaMusic/images/tilinca-stefan.jpg
the player in the right is playing the tilinca
The thing is, it has to be long enough, and it's very easy to make one. I did some.
I don't know Biosphere. I'll give it a check.THanks!