(https://d3mvlb3hz2g78.cloudfront.net/wp-content/uploads/2015/03/1425_3.jpg)
It sure looks like it, but there is another explanation. They are turning the egg/eggs in their nest, which they make in shallow depressions.
https://www.wonderopolis.org/wonder/do-ostriches-really-bury-their-heads-in-the-sand
It's a common misconception that an ostrich buries its head when danger is near.
Obviously, that would do jack all to avoid predators and make the ostrich an even more vulnerable target. And anyone who's ever seen footage of an ostrich knows that they're spoiling for a fight against most threats; they're not cowardly in the least. And when they're up against impossible odds, they use their powerful legs to quickly flee. They don't survive alongside rhinos and lions by being dumb.