Exploding Pigeons

The tales of Spontaneous Human Combustion have been
thoroughly disproved in recent years. Forensic arson investigators
using rigorous testing and simulations have shown that
a majority of these cases happened like this: An overweight
person falls asleep while smoking in a closed room with
almost no drafts. Their chair, couch or bed catches fire, but
the lack of fresh oxygen limits it to a slow smolder that
consumes their bodies almost completely, fed by their body fat.
Once deprived of this fuel the fire extinguishes itself, leaving
the rest of the room virtually untouched.

That's all fine and dandy, but what explanation do the 'experts'
have for this?
Normally I would conclude that a cat ate the bird.
But how does that explain the missing grass and scorched dirt
at ground zero?
As soon as one mystery is solved, another takes it's place.
What an interesting world we live in.