Really difficult to argue, one way or the other at this stage. As usual, instead of letting speculation run rampant, why not wait for better evidence - in this case an autopsy result.
Forensically a couple of points do come to mind though. Lets just presume for arguments sake there was a UAV, and the bird was defending its nest against a perceived threat; would it be diving at the drone in a way that would expose its legs to the extent the rest of its body escaped any sort of injury?
A UAV the size of an
M2P or smaller I feel would not "cleanly" severe the bird's legs, as suggested has happened, and I would have thought an aircraft the size of an Inspire or bigger would simply be making enough noise to frighten the bird to fly off from an attack, even though one prop' alone might cause such traumatic injury - before crashing?
Birds of prey are not silly, having a survival instinct that goes back a very long way genetically!
As a footnote: DON't buy into the media's use of the word "drone". That just continues to perpetuate the tabloid use of such a word, which by virtue of how it is said in English immediately evokes anti sentiment feelings.
My suggestion is to use the mnemonic "UAV" and keep pushing that forward every time there is any discussion about unmanned aerial vehicles. UAV has a much softer tone than the word "DRONE", which can be preserved as the name of a military "
pilotless radio-controlled aircraft used for reconnaissance or bombing " (Collins Dictionary)!