Great auk (Pen Gwyn in Welsh), or, because the great auk had such large white circles on its head. When European explorers discovered what today are known as penguins in the Southern Hemisphere, they noticed their similar appearance to the great auk and named them after this bird, although biologically, they are not closely related. Whalers also lumped the northern and southern birds together under the common name "woggins". Standing about tall and weighing approximately as adult birds, the flightless great auk was the second-largest member of both its family and the order Charadriiformes, surpassed only by the mancalline "Miomancalla". The great
Evolution of birds more rigid ribcage with a carina and shoulders able to allow for a powerful upstroke, essential to sustained powered flight. Another improvement was the appearance of an alula, used to achieve better control of landing or flight at low speeds. They also had a more derived pygostyle, with a ploughshare-shaped end. An early example is "Yanornis". Many were coastal birds, strikingly resembling modern shorebirds, like "Ichthyornis", or ducks, like" Gansus". Some evolved as swimming hunters, like the Hesperornithiformes – a group of flightless divers resembling grebes and loons. While modern in most respects, most of these birds retained typical reptilian-like