The Whistle is used by captains to call idle or working Pikmin to them. This whistle is also used to rescue Pikmin from hazards such as fire, poison, or water. A small cursor the same color as the captain's light shows where the whistle will blow from. Holding the B button down makes the captain shoot a sound wave at the cursor, which causes a spectrum of colors to rotate around the cursor at a gradually increasing radius, and makes a whistling sound, which varies upon the captain whistling. Captain Olimar's, Alph's, Brittany's, and Captain Charlie's whistle is a pea whistle, Louie's is a train whistle, and the President's is a car horn. The maximum calling diameter of the whistle is about the same as the circular area an Onion lands on. This maximum can be increased in Pikmin 2 by collecting the Amplified Amplifier from the Shower Room, which increases the range tremendously with the Mega Tweeter upgrade. Another upgrade for the whistle called the Pluckaphone, which allows captains to pluck Pikmin sprouts from the ground instantly by calling at them. This upgrade can be received by collecting the Professional Noisemaker from the Submerged Castle.
In Pikmin 3, the cursor and whistle have taken on new looks. The cursor is now a simple circle with a dot in the center. The dot has a straight white line that leads to the captain. The whistle radius is a single color dashed line that gradually grows, and then sends a second dashed circle upwards, creating a cylindrical collumn of light. This is used to call Winged Pikmin that are flying too high for the normal whistle. The new captains in the game have visible whistles built into their helmets.
In the Gamecube games, the whistle cursor points in the same direction the captain is facing, but on the Wii versions you can move the cursor anywhere on the screen using the Wii Remote.
In Pikmin 2, there is an enemy called the Antenna Beetle which makes a whistle with its wings that can attract Pikmin and lead them into hazards.
In Super Smash Bros. Brawl, the whistle is used to gather and sort Pikmin. The move is called "Pikmin Order", and is done by pressing down and B at the same time. Unlike the main series games, it calls Pikmin from anywhere on the stage as opposed to only within the radius. It appears much the same as it does in Pikmin and Pikmin 2, but it is smaller, without a reticule, and lasts a shorter amount of time.
In the Nintendo Land attraction Pikmin Adventure, pressing ZL, ZR, or tapping the call icon on the Wii U gamepad will cause the Mii controlling Captain Olimar to whistle all Pikmin, including the other player Pikmin to him/her. This will cause all player Pikmin to stack on top of Olimar's head, which Olimar can now throw at enemies or other obstacles. Pikmin can refuse being called by shaking the Wii Remote. Much like Super Smash Bros. Brawl, Pikmin can be called from anywhere.