Dark-eyed Junco (IMAGE) Indiana University Caption An IU Bloomington researcher collects preen oil from a junco's uropygial gland into a small glass tube. The procedure is painless. Credit Jonathan Atwell Usage Restrictions None 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.