פירוש על קידושין 72:3

The sprinkling referred to is the sprinkling of the blood of a bird offering on the altar. That it must be offered by a male priest is derived from an inference from animal offerings. Even an Israelite may slaughter an animal offering, but only a priest can sprinkle its blood. So if only a priest can slaughter a bird offering, obviously only a priest can sprinkle its blood.