When birds bathe in water or cover themselves in dust they are actively maintaining their plumage. In well-watered areas bathing is most common, but during winter when things are a lot dryer – or in arid areas – sand dusting is more often observed.
Dust bathing is a very important part of a bird’s preening and plumage maintenance that keeps feathers in top condition. When they do this they get their bodies as low to the ground as possible, often with their bellies placed on the ground, they then vigorously wriggle their wings and body in a frantic manner as if they were trying to shake something off and then proceed to flap and ruffle their feathers but, in fact, its the complete opposite. They try to ensure the dust is worked as deeply into their feathers as possible so the bird’s feathers can absorb excess oil to help keep the feathers from becoming greasy and matted. Most birds use preening oil to preen their feathers to make sure they are in the best possible condition which assist in flight.
When it comes to ostriches however it is slightly different because they do not have a uropygial gland which is the oil gland possessed by the majority of birds, so they are reliant on dust-bathing to keep their feathers healthy and dry. Ostrich wing feathers are particularly important to them for mating displays, shading chicks, covering naked skin to conserve heat and for use as ‘rudders’ to help manoeuvrability while running.
It’s a fairly common occurrence to see birds dust-bathing in winter, but to see the largest bird in the world doing it is something I certainly wasn’t expecting! It’s a bit more dramatic when the practitioner weights over 100kg!