yes most will if they are shot
Yes it most likely will die from the pellet or shock.
It is likely. a close range headshot would do the trick.
If shot from a BB gun, yes, especially to a smaller animal such as a cat or a rabbit. Death would be rare from a BB shot but it would definitely be painful (unless you were shooting at a bird in which case the bird would probably die). BB's could also be dangerous to an animal if they were ingested (eaten) as they are plastic and cannot easily pass through the digestive system of most animals.
Nerf gun
A BB gun would be more powerful
Yes
You may find that it's against the law in some places. A BB gun is a poor choice. The bird will suffer before death. BB Guns are NOT designed for hunting.
No. Hunting is not allowed in City limits
BB is one of a number of standard pellet sizes of bird shot there are also "B" and "BBB" sizes, but BB is the most common. (Ball Bearing)
In the truest sense of the definition of "automatic", no a bb gun cannot be automatic. In function, however, a BB gun can be automatic. A good example would be the Drozd BB gun which fires full automatic, but used CO2 as the power source.
400fps can kill a bird from about 10 yards away. I have a 880 powerline daisy It will go through the bird. So ya it can
If its a BB Gun, Then Yes.