Why is that? The vulture seems - at least to me - like an odd choice for one of the holiest of deities in the Egyptian pantheon.
Apparently, the Egyptians believed all vultures to be female and thus strongly associated them with maternity. This belief gave birth to Nekhbet, the mother of mothers:
As its name suggests, the Egyptian Vulture was the sacred animal of the ancient Pharaohs; its appearance is immortalized in the Egyptian hieroglyphic alphabet as the letter A. Since the ancient Egyptians thought that all vultures were female and were spontaneously born from eggs without the intervention of a male, they linked these animals to purity and motherhood. In actuality, both genders happen to have the same appearance, the only difference being the larger size of the female. Nonetheless, they were held sacred to the mother goddess Isis; they were also elevated to the rank of deity in their own right as Nekhbet, patron of Upper Egypt and nurse of the Pharaoh. The priestesses of Nekhbet wore garments of white vulture feathers, and the goddess herself was often portrayed as a vulture-headed woman, her wings spread to provide protection, a circlet in her claws - the shen, symbol of infinity. Her cult was in fact linked to the eternal cycle of death and rebirth because of the vulture's role in the food chain as a scavenger and its supposed parthenogenesis; Nekhbet was venerated as the mother of mothers, who existed from the beginning.