Duck Hunt

Five doctors went duck hunting one day. After a time, a bird came winging overhead.
The first to react was the GP, who raised his shotgun, but then hesitated. "I'm not quite sure it's a duck," he said, "I think that I will have to get a second opinion." And of course by that time, the bird was long gone.
Another bird appeared. This time, the pediatrician drew a bead on it. He too, however, was unsure if it was really a duck in his sight. He said, "Besides, it might have babies. I'll have to do some more investigating," he muttered, as the creature made good its escape. Next to spy a bird flying was the sharp-eyed psychiatrist. Shotgun shouldered, he was more certain of his intended prey's identity. "Now, I know it's a duck, but does it know it's a duck?" The fortunate bird disappeared while the fellow wrestled with this a. Finally, a fourth fowl sped past and this time the surgeon's weapon pointed skywards.BOOM!! The surgeon lowered his smoking gun and turned nonchalantly to the pathologist beside him. "Go see if that was a duck, will you?"