I simply couldn't stand there and film a bird dying for 5 minutes. I would have shooed away the Sparrowhawk and killed the Magpie instantly.
I'm interested as to how many other animals take so long to actually kill their prey. On TV Nature programmes (the closest i'm likely to get) it normallyseems to be over in a few seconds.
I think that I'm saying I appear to be soppy.
But then surely you are potentially causing harm to either the young of the Sparrowhawk or the parent bird itself? You have no way of knowing when the parent/adult bird and, therefore, any young last fed.
Watching things like Springwatch it is evident that it only takes one or two days without food to weaken an adult bird and start nestlings killing each other. It is also evident that the catch rate for these birds of prey is woeful in most cases.
Hard though it may be to stand and watch, I would argue that it is natures way and you have to weigh up the lives of the Hunter and any young dependent upon the adult as well and if you can't watch .... walk away.