Tiny wire jails

My recent encounter with an escaped Zebra Finch got me to wondering about why, of all the creatures in the world that we put into cages, we put birds into the smallest ones. Birds are the one creature that can fly anywhere in the world and yet we put them in tiny wire jails. I suppose a similar case could be made for fish and small glass prisons. But when we think of freedom, we don't usually think of swimming free: we think of flying free. Many caged creatures are part of our food chain and their treatment is often inhumane. But caging birds out of spite, or jealousy, or dominance, or because of a myriad other human foibles, it is unworthy of us; supposedly the most consciously aware and emotionally sensitive of animals. European Goldfinches, like the one below, were once very popular caged birds. In time, the world came to discover and prize the exotic-looking birds of far-off places. In some places laws had to be enacted that stipulated cages had to be large enough to allow a bird to stretch its wings to their full, natural extension. In the USA, it is against the law to cage native species of bird (go figure). And don't get me started on zoos. I won't even take my grandchildren there anymore. Please comment if you wish.
BtheB

Wikipedia Photo