Poor little Birdie! He doesn't have a house to protect him from the wind and rain. So his buddies — Spike, Queenie, Goldie, and Fidget, who range in shape from tall, thin, and narrow to short, fat and wide—decide to help him find one.They fly all over the neighborhood, but each house they come to is either too tall, too wide, too fat or too short for Birdie, but perfect for one of them. Just when the skies begin to cloud over and things look their bleakest, Birdie's friends pitch in to build a house that's just right for Birdie.

Capacity is an important concept in geometry.