Migrating Mule Deer (IMAGE) University of Wyoming Caption Mule deer move across a sagebrush-covered basin in western Wyoming. New research shows that surface disturbance from energy development can hinder mule deer migrations when it exceeds 3 percent. Credit Joe Riis 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.