Some general remarks about extended techniques:

Alternative fingerings

There is no need to specify fingerings normally, so the use of alternative fingerings is generally left to the player. However, in specific cases notation consists of a verbal instruction and/or a fingering diagram.
Alternative fingerings:

Low hoots

The end barrel is pulled out and the mouthpiece turned inwards towards the player. An interesting effect, but with little carrying power. Notate with a verbal instruction.
Low hoots:

Whistle tones

Blowing a very small amount of air into the flute. Although this is a quiet and somewhat uncontrollable effect, it has more carrying power than might be supposed. Notate with a verbal instruction.
Whistle tones:

Multiphonics

Playing chords. In non-specific situations, notate by writing a bottom note with the word 'chord' above. For more specific notations, consult specialist manuals.
Multiphonics:



quartertones

Microtones


Intervals smaller than a semitone. Notations vary, but the examples above show a microtonal inflection and a quartertone. Microtones are especially difficult on the piccolo, where the holes are entirely covered by keys. They are mostly produced using lip inflection.
Microtones:

Key slaps

Sslapping instrument keys. Notate with x-shaped noteheads and verbal instruction. The larger the flute, the more effective and pitched the key slap.
Key slaps:

The Orchestra: A User's Manual is a free resource and will remain so. It still receives between 8,000 and 16,000 unique visits per month from all over the world. See the testimonials. Thanks to all the donations, I have been able to create this responsive re-design. But the movies and sound clips recorded in 2004 do show their age. I would really like to re-record everything and add many more techniques, especially for solo and ensemble writing. I estimate this will cost around £30,000. If you know a source of such funds, please contact me: a.hugill [at] bathspa.ac.uk