female reproductive organ, in the abdominal cavity next to the top lobe of the kidneys; inner area (medulla) is connective tissue with blood vessels and nerves, outer layer (cortex) is made up of follicles each of which produces a germ cell (oocyte); follicles collect yolk materials from the liver for the ovum and release them to the oviduct for fertilization by sperm; secretes hormones that stimulate courtship behaviors, development of the brood patch, gonadal recrudescence, production of ova and of materials for yolk and albumen, and calcium production for eggshells, and that help regulate the timing of ovulation; most birds, including Bald Eagles, have only the left ovary (and oviduct), the right being absent or vestigial