Okay guys, we are all forgetting one simple fact:
A BIRD'S BONES ARE THIN WALLED AND FRAGILE, A QUAD'S ARMS ARE NOT.
The plastic or aluminum of the quad's structure is much more durable than a bird's skeleton so the blade damage will be much more severe than a bird being sucked through. Going back to the "Bic" pen, it takes much more force to break the pen's outer tube than it does to break a much larger bird bone