http://www.mahoodsculpture.com/how-to-make-copper-sculptures/

How do concrete bird baths/sculptures hold up compared to other materials in longevity of life?
also what other materials are used to make these?
have seen some that are i think copper or bronze?
how does the concrete one compare to wear and logevity of other materials?
why so for this??
Thanks for your answers!
they look like bronze .but they are plastic ..just look at the price ..concrete are prone to frost after a few years ..real stone are nice but expensive ..mines`real plastic!
PT 4 / HOW TO BUILD A COPPER ROLLING BALL SCULPTURE by CHRIS CAPP