Читать книгу Nature’s Babies - Mike Dilger - Страница 14

By choosing a flightless lifestyle, the ostrich has been able to increase its size and weight to such an extent that it is now the world’s largest and heaviest bird. These features, together with their tremendous eyesight, phenomenal running speed and a vicious kick, enable them to protect themselves on the predator-riddled plains of eastern and southern Africa.

In the wild, ostriches are nomadic and will travel long distances in mixed-sex herds with other grazing animals such as zebra and antelope to track down the seeds, plant matter and odd insect which make up their diet. As ostriches lack teeth, they swallow stones to help grind up these tough foodstuffs in their gizzard. Although their wings are not used in flight, they are still large with a wingspan of over 2 m (6 ft 6 in), and male ostriches use them in elaborate mating displays when they compete for territory, social status and the all-important attentions of a small harem of females, or hens.

Once the dominant male has successfully fought off the competition, he will then mate with all of his females. This often leads to many of the hens laying their eggs in the same communal nest, resulting in the production of a clutch of over 30 eggs. Weighing in at 1.5kg (3 lb 5 oz) each, the world’s heaviest eggs are then incubated by the dominant hen and the male until they hatch after about 40 days. The father’s responsibilities do not stop there, as he then assumes sole control of the crèche, in order to both defend the hatchlings and also teach them what to feed on and how to find it.

Zebra

© Friu Polking/FLPA

Until they are able to fend for and defend themselves, ostrich chicks will always stick to safety in numbers.