article_snippet.sent: Normally, the graceful birds have a pink hue caused by the levels of beto-Carotene in the graceful birds diet.
article_snippet.sent: Experts believe a rare genetic irregularity known as "melanism" can generate more melanin than usual, turning a flamingo's feathers a dark colour.
highlights_snippet.sent: Dark colouring thought to be caused by genetic irregularity where Dark colouring can generate more melanin than usual .