The most northern situated penguin lives on the Galapagos Islands, 1100 km west of mainland Ecuador(South America). Maybe a few individuals crossed the equator and nest on the northern most island of the Galapagos, but that doesn't count.A possible explanation for their habitat could be the Humboldt current, which drove them northwards, but the equatorial counter current which comes from the north of the Galapagos could have stopped them from swimming further up north.But more likely is the following explanation :Many islands on the northern hemisphere are surrounded by sheer rocks, so penguins can't land on them or else are the habitat for dangerous predators, which especially applies to the coasts of the mainland. On the opposite, auks can nest in chasms where predators can't reach them, but aren't able to stand up against the extreme climates, that adelies and emperors have to face. So both are well adjusted to their own specific conditions of life.Neither of them would take advantage of moving.Several times, people have tried to release some caught penguins around northern Norway, but all those experiments failed.The fact that there are already animals, looking a lot like penguins, namely the Giant Auk (in Latin : pinguïnus impennis), could also be a reason why penguins don't live in the northern hemisphere.