Typically Oriented in design and workmanship are the graceful bamboo birdcages from the Far East, found everywhere from import shops to department stores.
All are so decorative that it's tempting to want to hang one in that unadorned spot. But if you don't own a bird or don't really want one, just forget the feathered friend and think of the cage as a display case for some special object.
Put a ceramic cat or two inside. Add a bouquet of bright flowers or a flowering plant. For conversational comment, put a miniature painting on a tiny easel, inside.
Try an open music book, a toy trumpet, a harp, or a toy piano. display a family trophy, a framed photo, sprays of eucalyptus, or a green pine bough tied with a big ribbon bow. And leave the cage door open if you wish. The soft warm tones of the natural bamboo seem to provide an effective neutral background for any object but the cage can always be spraypainted.