No obvious signs of trauma, but we have big picture windows and when the outisde reflections are strong, we get bird strikes. They don't appear "broken" in their head, neck, etc, although I haven't tried to comparing them to other dead birds.
So I'm liking the theory of it hitting a tree while engaging another bird as prey.
We think that squirrels never fall out of trees, but they do.
We think seals never drown, but they can.
We all think engineers never make mistakes, but do they do (rarely).
Yeah, bird screw up sometimes.