Fascinating, and troubling. I'd have never thought about the PVC pipes being death traps to birds.
I guess my old boss, a Nevada, Arizona, and Alaska explorationist employed by Phelps Dodge for decades, having staked many a claim by dropping wooden 4x4 posts out of helicopters (to be emplaced in the snow or the ground later, when weather or access would provide), would be intrigued.
I still run in to some 4x4 wooden posts in Pioneers of southwest MT.
Foy