Hi. On our front lawn we have areas that are mulched and we just recently laid down some new mulch we got from Lowes (in bags) as we've done every spring.

We've noticed what for lack of a better term looks like puffs of sawdust popping up throughout the mulch which weren't there when I laid it down.

Any ideas what it is and how it's getting there? I don't see any insects within those puffs milling about but they could be underneath I suppose, but I'm at a loss as to how they are forming and what they actually are.