improvisational music

I have an interest in transcribing jazz improvisations and placing that notated music on my web page for others to study. I had been under the impression that jazz improvisations are not subject to copyright, or that jazz musicians did not copyright their solos. A few years ago a colleague told me that a particular journal would not publish improvisations by a particular musician because he, through his attorney, threatened an infringement suit. Aside from the Fair Use considerations my questions are:

Regarding musical improvisation on jazz recordings (1) before the 1976 copyright law went into effect, (2) after the law became effective.

The song is covered under copyright, but that that copyright covers the melody (and lyrics) which may be present on as little as 15%-20% of the recording. The remaining portion is improvisation.

That improvisation is performed by musicians who are not the song's copyright holders, and that improvisation is based on the harmony of the song, which is not under copyright (many songs use identical harmony). Do the improvising musicians hold the copyright to their individual improvisations? Although the recording fixes the improvisation, the musician will never play the improvisation the same way ever again (and take pride in the fact that each improvisation is unique).

The improvisation could be considered a derivative work, even though it is a portion of a recording of a song whose copyright is held by another. Is the improvisation then the property of the copyright holder?

After the requirement for formalities partially ceased with the 1976 law completely ceased with the signing of the Berne Convention does the improvising musician hold the copyright from the moment of fixation on a recording (even though the intention was not to create a fixation of a musical melody but rather a transient improvisation)?

Before the change in law, does the improvising musician hold the copyright to the improvisation even though the copyright was never claimed and no notice was placed on the recording?

--
G. W. Sandy Schaefer
Director of Jazz Studies/Commercial Music
Chadron State College
sschaefer[_at_]csc.edu