Tony D. Williams is professor of ecological and evolutionary physiology and chair of biology at Simon Fraser University. His books include Physiological Adaptations for Breeding in Birds (Princeton). Scott Mc Williams is professor of wildlife ecology and physiology at the University of Rhode Island. Julia A. Clarke is the John A. Wilson Professor in Vertebrate Paleontology at the University of Texas at Austin. Elizabeth Mac Dougall-Shackleton is professor of biology at Western University in Ontario. Scott Mac Dougall-Shackleton is chair of the Department of Psychology at Western University in Ontario. Frances Bonier is a field biologist with a research focus on the ways animals respond to diverse challenges, including parasites, urbanization, and climate change. Chad Eliason is a postdoctoral fellow at the Field Museum of Natural History in Chicago.