The owl stood for the sound of M in the Egyptian alphabet. Though most ancient Egyptian words were written as groups of consonants, the vulture represented the sounds of the short A, the short E and the short O.
Editor’s note: The Owl and Vulture Hieroglyphs are among the multitude of designs Anita created for her “Stone in Paper: Ancient Egypt” exhibit at the 2002 OrigamiUSA convention. Photos of the display are available here. The Fold published diagrams for Anita’s Sphinx, also from the 2002 exhibit. You can find the article and diagrams here.