Ostriches | Struthioniformes

Struisvogelachtigen | Avestruces

Running birds from the oldest branch of the bird tree, the palaeognaths, recognised by a palate whose bones are heavy and set almost rigidly together. The breastbone is a flat plate without a keel, the wing muscles are much reduced, and the wings serve only for balance while running, for shading the chicks and for display; the power of flight has been lost. The feathers lack the hooklets that in other birds lock the barbs into a closed vane, so the plumage stays loose and plumed and sheds no water; there is no preen gland. All the power lies behind: long, heavily muscled legs with a strongly reduced number of toes, carrying running speeds no other bird reaches on foot, and a kick that serves as defence. The young hatch in down with their eyes open and walk from the first day, and the male takes a large share of the incubation and of the escorting of the brood.

Families in this order

Ostriches | Struthionidae1 speciesThe only bird with two toes: the inner one carries a broad, hoof-like nail and takes almost the entire weight, the outer is small and nailless. Neck and thighs are unfeathered, the eyes are the largest of any land animal and sit on a head held above the grass; the adult male is black with white flight and tail feathers, the female and immatures grey-brown. Laying is communal: in a scraped hollow the major hen keeps her own eggs at the centre and pushes those of the minor hens to the rim, where they seldom hatch; she incubates by day, the black male by night. The male's call is a deep, far-carrying three-syllable booming, delivered with the neck inflated and at a distance hard to tell from a lion. The food is grass, seed, leaves, flowers and succulents, with large quantities of grit; most of the water comes from the green matter itself, so the birds can live far from any drinking place.