Kargarok

Making their first appearance in The Wind Waker, Kargaroks (カーゴロック, Kaagorokku) are bird-like creatures that Link faces frequently in his quest.

The Wind Waker
Kargarocs (as their name was spelled in The Wind Waker, see Nintendo Gallery) were used by Ganon for surveillance and transportation of other monsters, such as Moblins, across the sea. The Kargarocs were easily defeated when roosting, and were also susceptible to arrows (and cannon fire) when airborne. Link could glean rare Golden Feathers from defeated Kargarocs, of which Link could give 10 to a guard on Dragon Roost Island in exchange for a Piece of Heart. These creatures bear a resemblance to the Helmaroc King, the giant bird that kidnapped Link's sister, Aryll.

The name "Kargaroc" is most probably derived from "Roc" (as in Roc's Feather), an item featured in various games in the Zelda series. Also, a "Roc" is a giant bird in Asian mythologies.

Twilight Princess
In Twilight Princess, Kargaroks have two distinct incarnations. The first is a common enemy in Hyrule Field, which attempts to knock Link off of Epona. Karagaroks can be easily dispatched with the sword, although this can be difficult on horseback. An alternative method is simply to fire arrows at it, Bomb Arrows being especially effective.

A Shadow Kargarok is a Kargarok that has been transformed by the effects of the Twilight Realm. It attacks in the same way as a normal Kargarok, although its appearance is different; its body is black, and its head is concave. A special Shadow Kargarok battle takes place upon entering Lake Hylia. Fyer spots a Bulblin from a distance, which must be approached. When it sees Link, it will use the nearby Hawk Grass to call a Shadow Kargarok and then hop on its back, shooting flaming arrows. Once defeated, Midna takes control of it and uses it to progress further.

Trivia

 * The computerized horn sound the Shadow Kargorok makes is similar to Articuno's cry in the Pokemon game series.