when aiming for the birds. Don't follow directly on them. Have a bit of the cursor ahead of them, so you are tracking their movements, and if you need too, just rain hell upon them with your attack. It's your dead drop, they made the mistake of holding onto it.
If you are interested in an ES Roleplay story go to the website in my quote
That shotgun blast of a power requires pinpoint accuracy. lol.
Just use a normal bolt with R1. Dead Drop pigeons are the only enemies in the game where the bolt will auto-aim and even home in, so you don't even need to be a good shot. You can shoot half a foot to the side of them and still nail 'em in one.