Black Swans

I am not sure if any zoo in the United States or Europe has black swans, but I hope somehow you all get to see once in your life time such a special bird. They have the elegance of white swans with extra distinction given by the shiny, undulating black feathers. Black swans can be found only in Australia, but have been introduced in New Zealand and not so successfully in England. I haven't been able to find much information on their evolution and how they relate to the white European swans, but that is just one more intriguing aspect with which black swans fascinate me.