Killing things

The other day I was driving to work and I saw a bird drop straight out of the sky onto the side of the road, and all I was thinking after that was should I drive back there and kill it? I mean, birds don't just drop out of the sky for no reason. It must have fallen off of the power line. Maybe it was deathly ill, in which case I should probably stay away. But what if it's just been severely wounded by like, another bird with a knife. He was just sitting there, minding his own business, sittin' on the power line, thinking about where to fly next and BAM (or some other onomatopoeia [yes, I had to look up how to spell that] signifying a stabbing sound [like SCHLICK]) the other bird stabs him! Were I that bird, I would love for some kind passerby to either 1.take me to the bird hospital or 2.since that's a stupid idea and way too expensive since I'm only a wild bird, put me out of my misery.
I didn't kill it, but sometimes I still wonder should I have?
I think this only because I was once told a story by a friend of how he saw a hurt groundhog by the side of the road and for some reason decided to get out of his car and check on it. Needless to say (actually, I probably do need to say it or you'll have no idea what happened next), the groundhog attacked him and he had to stomp it to death! . . . Of course, that's exactly what I thought, too. That can't be a real story. Why on earth would you stop to check on a wounded groundhog. That considerably more than crazy. No one would do that. So on my way home that day (this friend was also a neighbor) I drove past where he said it had happened, and sure enough, there it was. It was all stiff and puffed up, there on the side of the road. And that's why I'm glad we're friends, my friend.