An Owsla is a group of rabbits which consists of captains and officers, and are the primary "policemen" of the warren. The Owsla are comprised of strong, intelligent and clever rabbits, but sometimes a talented storyteller or a seer can become a member of the Owsla. The duties of an Owsla can be from garden raiders and patrollers to fighters, or a group of talented soldiers under a warlord. Owsla are second-years or older, defend the Chief Rabbit and his doe, and exercise the authorities of the warren. The captains of the Owsla report directly to the Chief Rabbit.
Notable Owsla officers in the novel are Holly and Bigwig of the Sandleford Warren, and Campion, Vervain, Chervil, Avens, and Groundsel of Efrafa. On Watership Down Warren, Bigwig was Captain of Owsla. However, as Hazel says in Tales from Watership Down about Watership Down's Owsla, "We're all in the Owsla, really."