Gary
Ever hear of singing or booming dunes? These are sand dunes made of grains so polished and spherical that they flow like water downslope when disturbed and resonate as they do. The booming dunes of the Sahara can be heard from miles away.
I certainly don't think what we are looking at here represents similar material, but they are yet another example of how weird eolian geology can get. Bulldust or not, this martian dust appears to be very very dry and dessicated.