[[birds]] --- [[galdr]] - high pitched voice, (IS THAT WHY VEDIC CHANT IS SO HIGH PITCHED?) - the bird's voice was also suitable for intercourse with ***ghosts*** because ***birds*** are a very widespread epiphany of the soul and the dead are also believed to ***emit a piercing sound***. So the priests may have been going "Oooouuuuuooooo". They certainly wore white headdresses. I'll call it the Scoobey Doo Theory.