An important component of upland hunting for hunters is their partnership with their canine hunting companion. The breed of dog chosen by a hunter should first and foremost fit the style of hunting of the hunter and then the primary type of game bird being hunted for the relationship to be successful. A puppy's training may begin when the dog is around 4 months old. Training often involves reinforcement of canine predator instinct, and some common training tools are: dog whistles, 6 & 20 ft choke leashes, and shock collars. A puppy can be brought into the field within a year, but dogs reach prime ability at closer to 3 or 4 years old.