The owls at the Great Ga'Hoole Tree are among the most respected colliers in the owl kingdoms. A lump of coal and a dried caterpillar are the symbols of the colliering chaw, because colliers are required to also join the Weather Interpretation chaw, which gives them the valuable knowledge and flying skills necessary to survive in a fire. Elvan is the head colliering Ryb, along with Ezylryb and Bubo. After Ezylryb's death, this chaw was taken over by Soren and Ruby.
Colliering is the art and skill of diving into forest fires in order to harvest coals and embers for blacksmiths. Owls have been known to be "fire-blinked," and many have a dreaded fear of crowning, which is when fire leaps from treetop to treetop and may suck up an owl without skillfull manuevering.
As seen in The Journey, colliers always work in groups of at least two, so that one owl on the ground is spotted by a companion. Owls can either work on the ground, or catch flying embers at middle or high points.