Flightless bird that require a significant amount of overall metabolic energy, ratites decrease their basal metabolic rate and conserve energy. A study looking at the basal rates of birds found a significant correlation between low basal rate and pectoral muscle mass in kiwis. On the contrary, flightless penguins exude an intermediate basal rate. This is likely because penguins have well-developed pectoral muscles for hunting and diving in the water. For ground feeding birds, a cursorial lifestyle is more economical and allows for easier access to dietary requirements. Flying birds have different wing and feather structures that make flying easier, while flightless birds'
Flightless cormorant and other small creatures. They feed near the sea floor and no more than 200 metres offshore. The flightless cormorant is the largest extant member of its family, in length and weighing , and its wings are about one-third the size that would be required for a bird of its proportions to fly. The keel on the breastbone, where birds attach the large muscles needed for flight, is also greatly reduced. The flightless cormorants look slightly like a duck, except for their short, stubby wings. The upperparts are blackish and the underparts are brown. The long beak is hooked at