Why We Use Predator Guards

This, dear friends, is why conscientious folks attach predator guards to nest boxes.  This nest box in my back forty has clearly been under assault, probably by a squirrel.  There are gnaw marks on the steel predator guard ring, and some critter made a go of chewing an alternate route into the box.  I imagine had the $1.59 ring not been installed whatever was in the box would have been toast pretty quickly.  Let this be a lesson to all.  Small purchases and a little extra effort can save lives!