The timing basis for copyright starts counting down at the date of first authorized publication, not at the state of conception. Well, pre-1976; the 1976 copyright act actually starts the clock from the date of fixation.<p>The essential problem with the Happy Birthday song is that no one is quite sure who created it, and thus no one is quite sure which publication (if any!) would be an actual authorized publication. It thus falls under really, really gray areas of the law.<p>It should be noted, however, that the most plausible scenario that could win a victory at court (in terms of being able to prove that copyright exists) would have the copyright expire in about 400 days anyways.