One thing that I’ve noticed about beginning whistlers is the lack of proper breathing, and note attack and note sustain. You’ve got to take a big deep breath before putting air into the instrument, then start the note by striking the tip of the tongue against the upper pallet and releasing the air in a steady stream. It’s like saying “tah” or “dah”, that way the note is started with a definite beginning. To keep a steady stream going you have to ration the air a little, the inclination after you take a deep breath is to waste it at the beginning and let out the air in a wooosh, then you’ve got no air left for the end of the phrase! If you just start blowing into the whistle without an attack on the note you get a oooooh, oooooohh, ooooo, sort of thing, which sounds like a child messing around with a whistle. The first note of a tune needs an attack. After you get the tune going then you can decide where to place subsequent tonguing.
Practice playing whole musical phrases in one breath, a phrase is a complete musical idea like for example Mary and her lamb:
Mary had a little lamb, little lamb, little lamb, Mary had a little lamb whose fleece was white as snow.
Now this little bit of the song is one musical idea, or a phrase, if you put a “dah” before every note you are tonguing every note, it’s a good idea to practice simple stuff like this and make it very fluid, very melodic. Try to make the notes touch each other, in other words have no gap between them, after the initial attack keep the air stream steady, the only interruption being made by the tongue as you raise it up to the pallette to produce the next note by saying “tah” or “dah” again.
I’ve heard more than a few whistlers hacking up phrases simply because they run out of air! Breathe deep, finish the phrase (or well planned portion of a phrase) take another breath and keep on playing. It’s sort of like completing a sentence while you’re talking, before taking a breath.
I think a lot of people get a miscoception about tonguing on the whistle because the whistle really doesn’t require a lot of air compared to some instruments, and good players make things sound really quite fluid, but like Eldarion said, they really are putting a lot of tonguing in there.
It takes a little practice, sitting up, taking quick deep breaths, letting the air out in a steady manner. Getting a good attack, sustain, and release of tones also takes a bit of practice. Some people get this stuff eventually by trial and error, but if you’ve never had any formal training on a wind instrument the going can be a little slow, especially at first. So, if you can find a good whistle player or saxophonist, or tombonist or whatever, see if they can help you out with basic technique, it’ll help things out in the long run if you take a little time to get started properly.
Being an ex tuba player I could go on and on and on about breathing and phrasing and that sort of thing, but I’ll climb down from the soabox now.