When I inspected my colonies today one of the had what appeared to be sawdust. It was like wet wood mixed with yellow flakes. It was nearly blocking the entrance and was on the ground in front of the hive. My other colonies do not have this. This is my first winter keeping bees and I have not send a reference to this in any of the books I have. Does anyone have any ideas what this might be, and do I need to be concerned. Thanks, Bill at Bent Holly Farms Brighton, Tennessee