Hornbill (IMAGE) Field Museum Caption Several birds that look very different, including woodpeckers, hawks, owls and hornbills (photographed here) are all closely related to perching birds, the largest order of living birds, representing more than half of all avian species. Credit Photo by Sushma Reddy, courtesy of the Field Museum. Usage Restrictions This photo may only be used by the media and only in connection with this news story. 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.