Hi Dwayne and thanks for your question and picture of the mounds in your new pole barn. Unfortunately I can't tell what they are from the picture but there are some things you can try.

See if there is a rodent-sized hole up under the wood near the mounds. The rodent would be removing enough material that you should be able to see or feel a definite hole.

For ants or termites, look for signs of movement or take a vacuum to the area the droppings seem to be coming from and you should be able to find a living specimen.

If these tactics don't give you an identification, see if you can identify what the droppings are made of or take some in to the Clackamas County Extension office in a plastic bag along with the picture you sent and leave them for someone to identify.

Last possibility, send me some more pictures with better definition (it gets blurry when I enlarge the image) and I'll try again.

Hope one of these works!