Marine life same environmental problems and feeding niches have resulted in similar adaptations. Examples include albatross, penguins, gannets, and auks. In general, marine birds live longer, breed later and have fewer young than terrestrial 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. They feed both at the ocean's surface and below it, and even feed on each other. Marine birds can
Cuban flightless crane Cuban flightless crane The Cuban flightless crane ("Grus cubensis") is a large, extinct species of crane that was endemic to the island of Cuba in the Caribbean. The remains were found in Pleistocene deposits in Pinar del Rio. Probably derived from an early invasion of sandhill cranes from North America, it differed from that species by, as well as larger size, having a proportionately broader bill, stockier legs, and with reduced wings and pectoral girdle indicating that it may have been flightless. Currently, the only extant Caribbean crane is the Cuban sandhill crane, "Antigone canadensis nesiotes", an endangered subspecies of