Acknowledgments

Unpublished data and input were provided by R. Browning, R. Butler, C. Elphick, C. Ely, R. Gerstenberg, C. Gratto-Trevor, B. Harrington, R. Holmes, J. Jehl, B. Kus, R. Lanctot, D. Norton, L. Oring, G. Page, D. Parmelee, D. Paulson, M. Rubega, K. Russel, S. Senner, S. Skagen, D. Troy, H. Wilson, and S. Warnock. Egg data were supplied by the Western Foundation of Vertebrate Zoology and L. Kiff. N. Holmgren and P. Wenink graciously provided copies of their dissertations. Sonograms were kindly supplied by E. Miller. Unpublished data were collected by NDW with support from San Diego State University, University of California, Davis, Point Reyes Bird Observatory, and Troy Ecological Research Associates, and by REG with the support of the U.S Department of Interior, Fish and Wildlife Service, U.S. Department of Commerce, and National Oceanic and Atmospheric Administration. Support during the writing stage of this account for NDW came from the Canadian Wildlife Service, Simon Fraser University, and the University of Nevada, Reno. Drafts of this contribution were reviewed and improved by C. Handel, R. Holmes, J. Jehl, A. Poole, D. Troy, and S. Warnock.