Avian nasal salt glands are crescent-shaped organs that lie in shallow depressions in the frontal bones above the eyes in birds such as gulls, fulmars and petrels. In other birds they are found along the border of the frontal bone within the upper orbital membrane (curlews, geese and ducks), under the nasal bone (falcons and bustards), along the anterior border of the eye orbit (parrots), or under the eye beneath the orbital membrane