Female Falsetto?

Opera singers often talk about the "whistle register," in women, which includes the E above high C and higher. People sometimes call this the "falsetto" register of a woman's voice.

From wikipedia:

"In European classical music, the whistle register is used primarily by coloratura sopranos. Many parts in the coloratura soprano repertoire extend beyond "high C" and often extend up to high F (F6). Although many coloratura sopranos use whistle tone vocal production to sing these notes, some operatic sopranos are capable of singing up to "high F" (F6) without utilizing the vocal production associated with the whistle register but remaining in the modal register. That being said, most coloratura sopranos do utilize the whistle register, particularly when singing staccato notes in rapid succession, during high trills, or other elaborate coloratura ornamentation in the upper tessitura. Rarely will coloraturas use whistle tone when doing high extended notes. However, singers like Mado Robin were noted for doing so. Also, some rare coloratura sopranos do not need to use whistle register at all. Probably the best-known example of the whistle register in European classical music is in the "Queen of the Night" aria (properly titled "Der Hölle Rache kocht in meinem Herzen") [http://www.youtube.com/watch?v=_ufeyarJxNQ] from the Mozart opera Die Zauberflöte; it calls for pitches up to F6"