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
Tit (bird) caching, hoarding supplies of food during the winter. Tits are cavity-nesting birds, typically using trees, although "Pseudopodoces" builds a nest on the ground. Most tree-nesting tits excavate their nests, and clutch sizes are generally large for altricial birds, ranging from usually two eggs in the rufous-vented tit of the Himalayas to as many as 10 to 14 in the blue tit of Europe. In favourable conditions, this species had laid as many as 19 eggs, which is the largest clutch of any altricial bird. Most tits are multibrooded, a necessary strategy to cope with either the harsh winters in which