Skeet Shooting: You have 25 shotgun shells to shoot at 25 "Birds."
However, there isn't necessarily 25 stations to go to, hence there can be more then one "Bird" per station. I believe there's 17 stations total. This gives roughly 8 stations that give double birds in one way or another.
Unlike Trapshooting (in which the bird comes from one station only with rotations in a 90 degree arc), the birds here can cut across sharply, they can go out, straight out, they can even come at you.