This series of photos shows a Marsh Wren dust-bathing. This species normally hides in cattails and other tall vegetation, so it was quite a treat to see this bird out in the open for so long. Wrens will often bathe in water and then dust. It is thought that sifting dust through the plumage helps to control parasites.
Ethical Birder 
I bet that was fun to see. I have to admit that I might have mid-IDed that if I had seen it in the rock like that. I so often ID wrens by the habitat.