Acknowledgments

Unpublished observations were generously provided by R. E. Gill, C. Gratto-Trevor, J. R. Jehl, W. Lin, G. Luknar, B. J. McCaffery, and J. Obst. Data on Hawaii records were provided by R. Pyle, and on egg sets by L. Kiff of the Western Foundation of Vertebrate Zoology. N. Brokaw generously helped EPM with field work, locating references, and reviewing the manuscript. B. Harrington provided valuable comments and help with references. P. Yeudall of the Canadian Wildlife Service helped MAS locate references. J. R. Jehl and W. Lin made valuable comments on the account. We thank P. Z. Antas, R. D. Bayer, R. Bishop, S. Bondrup-Nielsen, G. Cox, L. Dickson, W. Harrington, R. Kreba, R. I. G. Morrison, G. W. Page, W. Peterson, G. Rising, and E. Seale for comments, information, and help with field work.

F. Cooke, R. Swainson, and S. Swainson provided MAS with accommodations during field work, and the Saskatchewan Wetland Conservation Corporation provided support during part of the writing. Dartmouth College, the Smithsonian Tropical Research Institute, and the Manomet Observatory provided EPM with logistical and financial support during field work or writing; the Churchill Northern Studies Centre and the Massachusetts Audubon Society provided logistical support during field work. Research was supported by grants from the National Research Council and Ontario Graduate Scholarships (MAS), and by the American Museum of Natural History’s Chapman Fund, the Field Museum of Natural History’s Schmidt Fund, and Sigma Xi (EPM). The illustration on page 24 is by R. V. Clem, from the archives of the Ewell Sale Stewart Library, the Academy of Natural Sciences of Philadelphia, used with permission.