Mountain Grouse (IMAGE) University of California - Davis Caption Coloration in birds is produced by both structural coloration in feathers and pigmentation, as seen in this mountain grouse in Olympic National Park. Credit Tim Caro/UC Davis Usage Restrictions Provide credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.