A Messenger arrives to report that the building of Cloudcuckooland is progressing with incredible speed: The army of bird workers have already finished the massive walls of the new city. Another Messenger arrives soon after, sounding the alarm and announcing that a winged god is flying through the city.

The goddess Iris, the messenger of the gods, enters, probably suspended on a crane. Peisetairos stops her and demands to know what she is doing, and Iris responds indignantly by saying that Zeus has sent her to tell humans to make sacrifices to the gods. Peisetairos sends her away, telling her, “The birds have now become new gods for men” (1236). The birds will now prevent any human sacrifices from reaching the Olympian gods.

As Iris leaves, furious, a Herald comes, singing the praises of Cloudcuckooland and describing the bird mania that the city has inspired in humanity. More human intruders promptly come to pester Peisetairos. A young man, the Father-Beater, arrives first, asking to live among the birds where, as he thinks, everything goes. Peisetairos gives him armor and sends him off to join the bird army. Kinesias, a dithyrambic poet, arrives next, followed by a young Informer, both offering their services, but Peisetairos sends them away.