Back off! (IMAGE) Society of Environmental Toxicology and Chemistry Caption Eight-week-old bald eagle nestling. At this age nestlings have the dark plumage of adults and can use their beaks and feet to fend off unwary biologists. Proper handlings skills are required to safely capture and sample these nestlings. Credit Jim Campbell-Spickler Usage Restrictions With attribution 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.