Agreed 10 fold.
I'm going to comment on the few here stunned that he put the rabbit down. I personally feel it was the right thing to do in that situation, and would have done the same or left the rabbit alone completely.
No reason to go muddying up nature by trying to treat that rabbit for his injuries, then the hawk would have gone without a meal, and perhaps it's young, then no more babies for that year... and you can see the chain reaction there.
It's much like those documentaries on national geographic, where you're are almost brought to tears watching the young seal pup being maimed and thrown around by the killer whale, but there is no reason for the photographers to step in and rescue the pup. That's just meddling in things we shouldn't be messing with.
Documenting nature is how we learn, it's something I most likely would have taken pictures of as well. Inquiring minds need to know.