Ostrich burying head?

[Waterbuffalo]

I beleive that Ostriches don't actually bury their heads in the sand, but why do people say that they do?

[Bellringer]

I have heard it said that they lower their heads so as to make a less obvious target for predators. It makes them look like a bush or something. It also gives the appearance of them burying their heads in the sand. Plus the fact that they have to get their heads down to eat.

[Cetti]

This is from the San Diego Zoo website:

When an ostrich senses danger and cannot run away, it flops to the ground and remains still, with its head and neck flat on the ground in front of it. Because the head and neck are lightly colored, they blend in with the color of the soil. From a distance, it just looks like the ostrich has buried its head in the sand, because only the body is visible.