Why don't the birds want tortoise to join them at the feast in the sky?
This is a traditional fable that Ekwefi tells Ezinma in Chapter 11. In the story, the land is suffering a drought, & it is a time of famine. But all the birds are invited to a feast in the sky, and when Tortoise finds out, he insists they bring him along.
The birds don't want to, because they know he cannot be trusted. Tortoise represents everything the Ibo people despise: he's lazy, dishonest, and likes to trick those around him. However, he's also a very convincing speaker, & so he persuades the birds to invite him. Of course, he practices his trickery, sure enough, & begins by telling them to select new names for the feast. Tortoise takes the name “All of you.” All of the birds give Tortoise feathers so he can fly to the feast with them.
When they arrive, the men in the sky think Tortoise is the king of the birds becuase of his unique shape, & mismatched feathers. They also declare they have prepared the feast for “all of you.” Since that's Tortoise’s new name, he eats the best portions of food and drinks two pots of palm wine. The birds only get scraps, and are naturally upset. They leave Tortoise in the sky, taking their feathers so he has no way to fly home. But Tortoise sends a message, asking his wife to put soft things around his homestead so he can jump down from the sky without danger. However, the birds are so angry, they ask his wife to bring out the hardest things she can find. When Tortoise jumps from the sky, he smashes his shell into a million pieces. This story explains why the Tortoise has a bumpy and cracked shell.