What items do attract towers skip?

[DeadWildFire]

I noticed my entrance attract tower was grabbing potatoes from my food area as they were harvested, so I did some remodeling so a tower was pulling it next to the kitchen/food storage. I attempted to do the same with where my village gets its water buckets from, but the tower doesn't target those. Are there any other items it doesn't target?

[Tiberiumkyle]

Basic rocks and wood are the only other things I know they'll ignore.