during the full moon(A University of New Orleans study says that 81 percent of mental health professionals believe that humans are prone to unusual behaviors during the full moon.ART Vancouver)
at the time of the full moon(At the time of the full moon, the singing was louder and was heard nightly. One of the witnesses recorded it, and the singing was preceded by a faint voice crying for help. (Janet & Colin Bord, "Unexplained Mysteries of The 20th Century")ART Vancouver)
