Seabirds are birds that have adapted to life within the marine environment. Seabirds can be highly pelagic, coastal, or in some cases spend a part of the year away from the sea entirely.The pelagic zone, also known as the open-ocean zone, is the part of a body of water which is located in the open water column, that is the part of the ocean that is not near the coast or continental shelf. The pelagic zone is further divided into sections creating a number of sub-zones based on their different ecological characteristics. These characteristics are roughly a function of depth.Seabirds and humans have a long history together: they have provided food to hunters, guided fishermen to fishing stocks and led sailors to land. Many species are currently threatened by human activities, and conservation efforts are under way.While sea birds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations. In general, seabirds live longer, breed later and have fewer young than other birds do, but they invest a great deal of time in their young. Most species nest in colonies, which can vary in size from a few dozen birds to millions.Many species are famous for undertaking long annual migrations, crossing the equator or circumnavigating the Earth in some cases.
From the ocean bursts a shiny five-year-old male puffin carrying a dozen small herring in his beak. It is August on the coast of Iceland, and the air is filled with the deep garbled growls of hundreds of puffins. The social birds have come to shore for the short breeding season, and the rocky banks are dotted with their squat, football-shaped bodies.