First we should define both a switch and old fall.
Switch
Quote:
Switch - page 27,
In Senior and Master Hunting Tests a dog that goes to the area of a fall, hunts, fails to find, and then leaves the area to hunt for another fall, or that drops a bird it is retrieving and goes for another, shall be considered to have switched. Unless in the opinion of the Judges there exist valid mitigating circumstances, a dog that switches shall be scored “0” in Perseverance in Senior and Master Hunting Tests.
page 43
Switching birds implies that a dog gives up in its hunt after a search, leaves the area, and goes for another bird, or when it drops a bird it is retrieving and goes for another. Except in the latter case, a dog shall not be scored for lack of Perseverance unless it goes to the area of a fall, hunts, fails to find, and then leaves that area to hunt for another fall. It shall not be considered as a lack of Perseverance, if, while on the way to one fall, the dog sees or finds another bird and retrieves it first; or, if on the way to one fall but long before it reaches the area of the fall, it changes its direction and goes for another bird.
Old Fall
Quote:
Page 27
A dog that returns to the area of a fall or a blind that it has previously retrieved and establishes another hunt shall be considered to have returned to an old fall. Unless in the opinion of the Judges there exist valid mitigating circumstances, a dog that returns to an old fall shall be scored low in Perseverance and/or Marking, even to the extent of awarding a grade of “zero.”