Guay
Guays are small, crow-like creatures that appear in several games.
The Legend of Zelda: A Link to the Past
Guays first appeared in A Link to the Past. They are often seen perched in trees, and attack when someone approaches.
The Legend of Zelda: Ocarina of Time
In Ocarina of Time, Guays are encountered mainly in large areas with lots of space, namely, Lon Lon Ranch (as a Child), Lake Hylia (as an Adult), and the Desert Colossus. They attack Link on sight by by dive-bombing him. They are one of three enemies in the game that have an enlarged version that comes after killing many small ones, along with Stalchilds and Leevers.
The Legend of Zelda: Majora's Mask
Guays are the same in Majora's Mask, excluding the enlarged variant and rarity similarities. They are less common in Majora's Mask, most appearing only in Ikana Canyon. Aside from that, one lone Guay can always be seen flying around the exterior of Clock Town. It ignores Link unless he plays one of the four temple songs, at which point it will begin dropping progressively more valuable rupees.
The Legend of Zelda: The Minish Cap
Guays in The Minish Cap behave in much the same way as in A Link to the Past, but play a more prominent role. When Link visits Dampe, he recieved the gate key needed to open the door to the graveyard. When he exited the house, a Guay swooped down, stole the key, and retreated to its nest. Link traveled to the nest and was able to destroy it and steal the key back.
The Legend of Zelda: Twilight Princess
Guays in Twilight Princess are larger, slow-moving, and encountered in large groups. These groups are often found in trees, and fly out of the tree as Link approaches. Killing a group of Guays will often cause a small pile of rupees to fall from the sky. At Lake Hylia, if you stand on the island with the Zora by the cannon. You can use the hawk-eye/bow combo to search the sky for a large flock of Guays. Kill every single one of them and a pile of rupees will fall, the pile is worth 73 rupees!