Southern Ocean – fairly uniform temperatures of the deep ocean at the poles and the equator which differ by no more than 5 °C, and the major current systems or marine conveyor belt which transport egg and larva stages. The rocky shores of mainland Antarctica and its offshore islands provide nesting space for over 100 million birds every spring. These nesters include species of albatrosses, petrels, skuas, gulls and terns. The insectivorous South Georgia pipit is endemic to South Georgia and some smaller surrounding islands. Freshwater ducks inhabit South Georgia and the Kerguelen Islands. The flightless penguins are all located in the
Flightless cormorant bird eventually became flightless. Indeed, wings trapping air among flight feathers are likely to have been a disadvantage to the cormorants which dive from the surface. However, since their discovery by man, the islands have not remained free of predators: cats, dogs, and pigs have been introduced to the islands over the years. In addition, these birds have no fear of humans and can easily be approached and picked up. In the past, introduced feral dogs were a great threat to the species on Isabela, but they have since been eradicated from the island. Future introduction of rats or cats