Use of debris by burrowing owls

Some of our previous research showed that nesting burrowing owls line their burrows with mammal manure to attract insect prey.  But burrowing owls also commonly use other materials such as paper and plastic.  These other materials seemingly contradict the prey-attraction hypothesis.   We have just published a paper that explores the use of these other materials, and if burrowing owls prefer manure to other materials?   .pdf