Bison rustlers

Bison rustlers are Earth Kingdom poachers who primarily trap flying bison calves near the Northern Air Temple for sale in black markets, including exotic food establishments in the Upper Ring of Ba Sing Se.

History
Due to the sky bison's value as an endangered species, the bison rustlers began trapping calves for sale in numerous markets throughout the Earth Kingdom, even managing to acquire business with Earth Queen Hou-Ting and the upper echelon of citizens in Ba Sing Se who enjoyed exotic meats.

In 171 AG, the rustlers began to operate more covertly due to the arrival of numerous airbenders to the Northern Air Temple. Despite their attempts to remain undiscovered, the poachers kidnapped Jinora and Kai, resolving to sell the two in Ba Sing Se along with four newborn calves. However, Jinora was able to use her connection with spirits to warn Bum-Ju about her predicament, prompting the spirit to inform Bumi who consequently gathered all of the airbending recruits to lead in an ambush of the campgrounds.

After escaping his cage by picking the lock, Kai assisted the other recruits in subduing the rustlers, most of whom were eventually subdued using airbending. Despite the leader's attempts to escape on his truck with Jinora and three calves, the poacher was pursued by Kai, Tenzin, and three adult flying bison, forcing him to surrender. He was subsequently caged along with the rest of his men, who Bumi reminded never to mess with an airbender's bison.

Trivia

 * The leader of the bison rustlers wears a sky bison pelt on his back.