Birds are regarded as the intellectual leaders of the world. Most birds live in the northern forest at the base of Ptera Peak. Some of them serve the pigs by assisting with indoctrination of sheep, but most of them seem to exist independently of the interactions between other races. Birds are fairly integrated with sheep in Fleece City and the quarry, but they do not appear to have a presence in the dogs' southern forest or in the Megatropolis. Birds are employed as figureheads in This Little Piggy Primary School, the quarry church, and University.
As part of the terms negotiated after the Canine-Avian War, the birds were allowed to openly worship Optera and encourage sheep to do so as well. This was the genesis of the Church of the Goddess movement.
About half of birds worship Optera. They work to promote her values of intelligence, philosophy, and discovery. The other half of birds have declared themselves free of belief in any god, leading to a feud between the Church of the Goddess and the skeptics. The birds keep this schism private, considering it to be an embarrassment.
Birds are notorious for being difficult for the pigs to control, and the forest village that is the heart of bird society is free of pig propaganda. At present, pigs mainly rely on the private feud to keep birds occupied and out of the Chugg Corporation's way.
Optera crafts Ponder ostensibly to provide an intellectual leader that can unite both factions of birds. It is only later that Ponder's true purpose is revealed.
- A wide variety of bird species live together at Ptera Peak, including common birds, exotic birds, and birds of prey. Pigeons, parakeets, parrots, screech owls, grackles, magpies, and several other species are mentioned throughout the books.
- Wender the mail carrier is a blue jay.
- The teacher at This Little Piggy Primary School is a green parrot.
- The quarry church is led by an egret.
- The Flaxer family is a group of four canaries.
- Caper is a cape horned owl.
- Specter is a condor, and his two lackeys are ravens.
- Chugg Cybernetics produces clone ospreys to use as sentries and soldiers.
- Ponder is modeled after a scarlet macaw.