The People of the Wind

Read The People of the Wind Storyline:

Like two giants the old enemies faced each other across the reaches of the galaxy — the Terran Empire and the Ythrian Domain. Terra was a Leviathan, encroaching ever further among the stars, promising peace and prosperity — but at the price of freedom. Ythri was smaller, but an empire in its own right, peopled by birdlike beings with a civilization and intellect that easily matched Terra’s own.
Nominated for Nebula Award in 1973, Hugo and Locus awards in 1974.