"Procellariiformes drink seawater, so they have to excrete excess salt. All birds have an enlarged nasal gland at the base of the bill, above the eyes, and in the Procellariiformes the gland is active. In general terms, the salt gland removes salt from the system and forms a 5 percent saline solution that drips out of the nostrils, or is forcibly ejected in some petrels. The processes behind this involve high levels of sodium ion reabsorption into the blood plasma within the kidneys, and secretion of sodium chloride via the salt glands using less water than was absorbed, which essentially generates salt-free water for other physiological uses. This high efficiency of sodium ion absorption is attributed to mammalian-type nephrons" (Wiki_En (http://en.wikipedia.org/wiki/Procellariiformes#Morphology_and_flight)).