@Fernie: Calling names always is a great way to start a conversation.. I believe that we have a responsibility in our actions in the world. That means in some cases, you nurture and protect and in other situations you are humane which may require you to end the suffering of an animal.
I've learned that doing the right thing is not always pretty, gentle, or pleasant. I've had to assist quite a few animals including pets as they died. It isn't horrible, just hard. I believe it is far kinder to end pain and suffering in an animal than to just let it linger.
One does make value judgements. An eagle, I'd try to help, but not a pigeon.