How do seabirds filter seawater?

ever wonder where seabirds (gulls, pelicans, penguins, etc.) get their fresh water? they have a pair of salt glands (supraorbital) that filter out the salt and turn this into brine that drips out their noses. ever see a gull tilting his head down and water drips out? that's what's happening. Other animals that also have salt glands, include sea turtles, crocodiles (crocodile tears) and sharks.