Hawk Grass is a variation of grass that appears in Twilight Princess. Its sole purpose is to summon a nearby Hawk. Once Link has done so, he can then choose the direction he wishes to send the flying animal in. This item can be very useful, especially when Link attempts to get things that are either too faraway or too high. Other characters, such as Rusl and Hanch, also summon hawks throughout the game. Rusl in particular is able to summon a hawk without the use of Hawk Grass. Later in the game, Hanch uses a nearby hawk to drive away Wolf Link in order to defend himself.
Hawk Grass can be found almost anywhere, and is introduced almost immediately to Link at the very beginning of the game. This type of grass is vital if Link wishes to retrieve the Baby Cradle for Uli. Once Link has retrieved the cradle from the Monkey, Uli gifts him with the Fishing Rod. Link can also use the Hawk Grass to knock down a nearby beehive, which he is able to obtain Bee Larva from.
Later on in the game, Wolf Link encounters a Shadow Bulblin, who uses the grass to call upon a Shadow Kargarok. Once Link has knocked off the Bulblin, Midna is able to tame the beast and Link has to navigate it through Zora's River. After the light is restored to the Lanayru Province, Link in Wolf form can howl at the grass. This summons a regular Kargarok and the objective is to pop fruit-shaped balloons. Link can gain a Piece of Heart and 100 Rupees from Plumm if he achieves a high enough score. Alternatively, Hawk Grass can also be found at Death Mountain and at the Sacred Grove; however, it does not serve much importance in these areas.