Acknowledgments

We would like to thank the Alberta Conservation Association and the Provincial Museum of Alberta, Alberta Community Development for their financial support of this project. Special thanks are extended to Doug Leighton, Dick Cannings, Eric Tull and Roger Brown for providing insight and access to personal records on Empidonax. The Federation of Alberta Naturalists supplied Atlas records. Kevin Van Tighem (Parks Canada) and Peter Achuff (Parks Canada) assisted with the acquisition of the proper permits for the national parks. We are also pleased to acknowledge the assistance of Trevor Wiens, Glen Semenchuk and Bill Weimannin the field. The Kananaskis Centre for Environmental Research (University of Calgary) provided ideal accommodation in support of field studies. The manuscript was read and much improved by the comments of Jim Burns (Provincial Museum of Alberta), Alwynne Beaudoin (PMA), David Prescott (Alberta Conservation Association), and Isabelle Michaud (ACA).