Athena winged a heron close to their path
And veering right. Neither man could see it
Scanning the night sky, they only heard its cry.

– Homer

The Iliad, Book 10, lines 322-324. When Diomedes and Odysseus move out in their war gear, goddess Athena sends them a lucky sign. It is a heron flying across the night sky, whose cry they are pleased to hear.