Above a small rocky island in Glacier Bay, hundreds of grey and white seagulls wheel and dive. They're black-legged kittiwakes and this is a summer nesting colony. Nesting is one of the only times kittiwakes come to land. A true gull of the sea, kittiwakes spend most of their lives away from land. They don't need freshwater and drink only seawater. Like many ocean-going birds, kittiwakes have a special gland that desalinates their blood and secretes an extremely salty fluid into their nasal cavities, which then drips from their nostrils.
There are two kinds of kittiwakes, black-legged and red-legged kittiwakes. Red-legged kittiwakes are uncommon, they're mainly found in the Gulf of Alaska and more than 90 percent of Alaska's red legged kittiwakes nest on the Pribilof Islands in the Bering Sea. These birds were profoundly impacted by the introduction of rats to the Pribilofs, which eat eggs and birds.
Black-legged kittiwakes are far more common and favor Arctic and subarctic waters across Western and eastern North America, as well as Scandinavia and eastern Siberia. Kittiwakes are the only cliff nesting gull, and they can nest on nearly vertical cliffs, laying one or two eggs in a small nest made of seaweed or moss. Some winter entirely at sea, others travel down the east and west coasts. In coastal New England states, Kittiwakes are also known as frost gulls, where their arrival in the autumn coincides with the first frosts. Their more common name, kittiwake, comes from the sound of their calls.