Whistling

Whistle is a skill and game mechanic in The Legend of Zelda: Breath of the Wild. Though it is automatically available from the start of the game, it serves little purpose at first.

Overview
In Breath of the Wild, Link can whistle by pressing down on the control pad and is available from the start. When performed Link will cup his hands and whistle the notes to Epona's Song. Whistling is primarily used to summon Link's Horse, though he must first have it registered and can only call a horse if it has been taken out of the Stable. Also unlike the Horse Call, Horse Grass, or Epona's Song used to summon his horse Epona in past games, the horse can only be summoned if it nearby and can reach Link's location as it simply calls them and does not make them warp to Link's location if they are too far away. If Link tries to summon it from too far away he will receive a message that states that the horse (which is referred to by its registered name) cannot hear Link's whistle and if it is unable to reach him, the message will state that the horse cannot reach him. If the horse is nearby when Link whistles the horse's mini-map icon will pulsate to indicate that it has heard him and is traveling to his location. Depending on the distance and environment it must travel through Link may have to wait for his horse to reach him after whistling. Whistling works on all registered horses regardless of their temperament or bond with Link.

In addition to calling horses, Link can also use whistling to call Wolf Link (summoned by using the Wolf Link amiibo with the amiibo Rune) to him after commanding him to stay.