Where do polar bears keep all their money?

I hold a small jungle, leafy and green, a tiny ecosystem behind a glass screen.

From trees I come in milky white, then shaped by heat to gain my might. I stretch and bend but still endure, made strong and firm through fire’s cure.

Fifth from the center, at least from our point of view. I've got two rings, that can hardly be seen. Just please don't stare at my giant red spot.

I'm an aviary type and yes my bones are hollow. At least my name carries no innuendo, like that little weirdo swallow.