Ostriches are flightless birds, and these birds have been forced to learn how to adapt without the capability to fly like the other birds. Their wings are too small to create enough lift for their 200-pound bodies. Wings are also a liability in terms of resources not being used, and the more ample birds are experts at converting food into reproduction and growth.
It is this same growth and lack of flight that facilitates the birds to fulfill the same niches their ancestors did, what they lack in ability; they make up for in speed. Also, it has been said that the mass extinction of the dinosaur population is the chief reason that the ostriches remain flightless.
Whenever ostriches are mentioned, the only characteristic we always remember about them is that they are flightless birds. This is true, but the reason behind it be must be known too. Ostriches can't fly actually because of their big size, because there are other big birds that can still fly. They can't fly because their breastbone lacks the keel part, which will allow them to fly like other birds. Other big birds have this, and that's why they can fly.
And if they could fly at all, their small wings can't be effective for this. Their inability to fly can also be attributed to how they have evolved over time. It is believed that their earlier ancestors could fly, but because of some evolutionary factors, they have lost that ability. Although they can't use their wings to fly, they use them for a lot of things. They maintain their balance with their wings.