Flightless bird Flightless bird Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species including the well known ratites (ostrich, emu, cassowary, rhea and kiwi) and penguins. The smallest flightless bird is the Inaccessible Island rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird, is the ostrich (2.7 m, 156 kg). Ostriches are farmed for their decorative feathers, meat and their skins, which are used to make leather. Many domesticated birds, such as the domestic chicken and domestic duck, have lost
Kangaroo Island emu shown are from "Ile Decrès", the French name for Kangaroo Island, but there is confusion over what is actually depicted. The two adult birds are labelled as a male and female of the same subspecies, surrounded by juveniles. The family-group shown is improbable, since breeding pairs of the mainland emu split up once the male begins incubating the eggs. Lesueur's preparatory sketches also indicate these may have been drawn after the captive birds in Jardin des Plantes, and not wild ones, which would have been harder to observe for extended periods. The Australian museum curator, Stephanie Pfennigwerth, has instead proposed