Acknowledgments
Data were collected by the Center of Whale Research under federal permits (Marine Mammal Protection Act permit 532-1822 and/or Department of Fisheries and Oceans license 2006-08/SARA-34) in both the United States and Canada, and the study was endorsed by the School of Psychology Ethics Committee at the University of Exeter. We thank the Center for Whale Research staff and volunteers, especially David Ellifrit and Erin Heydenreich; the Pacific Salmon Commission for salmon abundance data; and Matthew Collett, Rob Heathcote, and Chris Thomas for comments on the manuscript. This research was funded by a Natural Environment Research Council grant (NE/K01286X/1) to D.P.C., D.W.F., and M.A.C. Received: December 11, 2014 Revised: January 10, 2015 Accepted: January 15, 2015 Published: March 5, 2015