Birdman mainly tells the story of an old bird who ventured into a trap to talk to human beings in order to make them understand human greed.

In order to get out of danger safely, the old bird chatted with human beings and told three famous words. Every word keeps the old bird away from the hunter. The first sentence is: don't regret what you lost. Humans keep their promises and let the old birds go. The second sentence: don't believe it's impossible. Man let the old bird fly to the tree. Then the old bird lied to humans that he had a 30-meter-long gem. Then humans regretted it and bit themselves. I'm not even 20 meters, let alone a 30-meter gem! "

This fable tells us that greed is human nature, and greedy people have no good end.