The St. Aegolious Canyons are where hundreds upon thousands of owlets are moon blinked and used for "plain,humble servants of a higher good". (Dissecting pellets to search for flecks, hatching eggs, and occasionally going out to egg and chick snatch)
St. Aegolious Canyons (A.K.A St.Aggies) is lead by Skench the Ablah General and Spoorn who is second in command. Owlets are forced to participate in the moon march where the young chicks march under the full moon and stop to sleep in its shine. Doing so moon blinks the young owlet. The owlets are not allowed to sleep with their heads under their wings or their heads rested on their backs and must tip their beaks towards the full moon. During the moon march the owlets repeat their name until they completely forget it as a result of the moon blinking.
If an owlet somehow resists the moon blinking, like Soren and Gylfie, they will be placed into a white stone chamber off towards the side of the glaucidiums. The moon's shine is reflected fiercely off the white stone and it practically guarantees moon blinking.
The Pelletorium is a deep pit in the canyon full of hundreds of stationed owls, picking away at pellets, collecting bones, fur, feathers, and flecks. Third degree pickers pick for bones, pebbles, and teeth. Second degree pickers pick for feathers and fur. First degree pickers pick for flecks. Soren was given laughter therapy when he asked, "What are flecks?" As a result of laughter therapy, Soren was snatched, flown into the air, and his wings were plucked while the other owlets picking in the pelletorium laughed. He is nursed by Auntie (Finny) in his pit.
The pits are deep indents inside St. Aggies canyon. There, the owlets rest and take breaks. Two pit gaurdians that are mentioned in the book are Finny (Or Auntie and later on Nursey) and Unk (His real name is not given). Gylfie's pit gaurdian is Unk and Soren's is Auntie. Auntie occasionlyly slips Soren pieces of vole and allows hip to take naps out of sight. It is mentioned thta Unk also gives Gylfie bits of rattlesnake meat.
Soren and Gylfie escape St. Aggies woth the help from a Boreal Owl named Grimble. Grimble is murdered just as Soren and Gylfie fly away by Skench. Later on in the book series, St. Aggies is inflitrated by Pure Ones and Soren, Gylfie, Digger, Martin, Otulissa, Twilight, and Ruby are sent on a mission from the great Ga'Hoole tree to see what the Pure Ones are up to.
A turnfeather from the Pure Ones lets her fellow Pure Ones poke flecks into the nests of eggs and then takes them out. Twilight makes a commotion about how the real Pure Ones had just checked the nest moss and launches and attack of St. Aggies broodies against any Tyto Alba (Soren himself had to dodge some St. Aggies warriors.
Then awhile after Soren, Gylfie, Twilight, Digger, Martin, Otulissa, and Ruby escape the St. Aggies canyons it is conquered by the Pure Ones.