Seabirds such as gulls drink salt water and later excrete the extra salt.

The longer version

A bird's kidney cannot make urine saltier than its blood, so seabirds use a separate route. Paired nasal glands above the eyes pull salt out of the bloodstream and secrete a fluid several times saltier than seawater. The liquid drips or is shaken from the nostrils, which is why gulls look as though they are sneezing brine.

The gland works by pumping ions against a gradient, and it grows larger and more active in birds given salty water. It lets gulls, albatrosses and petrels stay at sea for months without fresh water. Human kidneys cannot manage this, which is why drinking seawater leaves a person thirstier, not less.

Where this entry sits

Here you will find feathered trivia about flight, migration, nests, eggs, and the songs birds sing. Expect short surprising facts on penguins, owls, hummingbirds, and other familiar birds from gardens, forests, wetlands, and distant coastlines. The full list sits on the Birds page, where every entry is listed in order.