This flight call guide was based on a foundation of knowledge about birds laid down by generations of ornithologists and observers of the natural world. Their work made it possible for us to pursue a systematic understanding of avian flight calls. In particular, we would like to acknowledge a number of others who shared an interest in avian night flight calls and left written documents for us to build on: Stanley Ball, Bill Cochran, Richard Graber, Bill Hamilton, Paul Howes, Henry Kopman, O.G. Libby, Gerald Thayer, Winsor Tyler (see their paper citations in References). Many others left short notes of call counts in various bird journals. We especially acknowledge Richard Graber, whose curiosity and prescience for the value of researching the identity and quantitative characteristics of avian nocturnal flight calling via audio recordings is an important landmark for the science of night flight call monitoring. We dedicate this reference guide to the memory of Dr. Graber's work.

        More generally we also acknowledge the work of Roger Tory Peterson and others in the 20th century who provided interfaces for the American public with North American aviculture. We must also single out the work of Chandler S. Robbins, who has not only committed his life to bird conservation but who has taught us the importance of population monitoring as a tool in this effort. It is with the same spirit, inspired by Chan, that we put forth this guide as a tool to further our understanding of migratory bird populations.

        This production spanned more than a decade and many people have contributed inspiration and shared their knowledge of bird vocalizations. In the early years of our effort, we were encouraged and inspired by a few keen birders who had heard these calls and could give us at least a rough verbal or phonetic description. In particular, we thank Will Russell, co-founder of WINGS, whose breadth of knowledge about bird vocalizations is legendary. Will’s early discussions on the distinction between Yellow and Blackpoll Warbler flight calls and his account of knowing Canada Warbler's night flight call were sources of inspiration in catalyzing this guide. We also thank David Sibley who seemed to have heard most of these flight calls at one time or another and was kind enough to share his recollection of the harder-to-hear calls with us. We are admiringly indebted to the simple but vital inspiration Will and David shared with us.

        Others provided important discussions and information on specific areas that also spurred us on. Chan Robbins gave us an inspiring description of Rose-breasted Grosbeak night flight call. Curtis Marantz provided stimulating descriptions of Mourning and McGillivray's Warbler flight calls. Kimball Garrett and Kenn Kaufman helped confirm our suspicion of Wilson's Warbler's flight call. Such tidbits of information were vital in encouraging our work.

        During our time in the field, we benefited from birders who were able to help us either find or identify the birds we were trying to record. For this, we with to thank Parker Backstrom, Dave Czaplak, Jim Dowdell, Jon Dunn, Kim Eckert, Vince Elia, Shawneen Finnegan, Mark Hoffman, Julian Hough, Steve Howell, Marshall Iliff, Tony Leukering, Evan Obercian, John O’Brien, Paul O’Brien, Bill Pranty, Will Russell, Scott Seltman, David Sibley, Jim Stasz, Mark Stevenson, Chris Wood, Matt Young, and Louise Zemaitis. In particular, we thank Richard Crossley for spending countless hours with us watching the morning flight in Cape May and coaching us on how to identify warblers in flight.

        For reviewing and making helpful comments on earlier drafts or on specific species, we wish to thank Kim Eckert, Alvaro Jaramillo, Tony Leukering, Scott Seltman, and Chris Wood. 

        For their in-depth reviews of the whole guide, we are indebted to Will Russell, Evan Obercian, and Ned Brinkley. Will Russell supported this project from the beginning, provided valuable advise all along the way, and thoroughly reviewed two different drafts of the guide. Evan Obercian became a primary consultant on this guide during our last field season and approached that role with a fresh, vibrant, youthful knowledge - one that challenged our own. He spent many hours with us helping to refine the flight call descriptions and did a thorough review of an earlier draft. Ned Brinkley witnessed the development of this guide from its early stages and his friendship and inspiration helped bouy our spirits over the many years of the project. His thorough review of the final edition and last minute copy-editing gave us the confidence that our guide was ready to be released.

        Lang Elliott was a huge resource for this guide. He provided inspiration, recordings, and graphic design work - he was a true brother for us over the whole period of this project’s development. Lang was instrumental in encouraging us to move from the format of an audio CD to that of a CD-ROM. As it came time to put the guide together it seemed that we had done a great job of getting examples of the harder to get flight calls but had overlooked those from many common species. We were not overly concerned because we knew we could get the examples we needed from Lang. Finally, Lang came in at a critical time and took charge of the graphic design of the CD-ROM case and produced an outstanding design.

        For providing valuable recordings for research or for use in the guide, we thank Michael Green, Stephanie Jones, Geoff Keller, Daniel F. Lane, Sarah Mabey, Ted Mack, John O’Brien, and Chris Wood. The Macauley Library of Natural Sounds kindly donated use of a diurnal recording of Gray-cheeked Thrush flight calls recorded by Peter Paul Kellogg and Arthur Allen. We also acquired several recordings from the Borror Lab of Bioacoustics. We give thanks to these and other similar institutions and honor their noble conservation and public education mission in archiving important audio recordings of natural sounds for the future.

        Greg Budney, Chris Clark, Katy Payne, Ken Rosenberg and Charles Walcott of the Cornell Laboratory of Ornithology played an important role in providing encouragement and facilitating use of the Lab of Ornithology’s resources and expertise in the early stages of our work. This is particularly true with regard to instruction in effective natural sound recording and in spectrographic analysis of bird calls. The whole Cornell Lab of O staff played a supportive role in our effort and, in particular, we would like to acknowledge Steve Sibley, Harold Mills, Steve Mitchell, Dave Mellinger, Russ Chariff, Kurt Fristrup, Bob Grotke, and Connie Gordon for their direct support and encouragement for this work. Former Cornell professor Richard B. Fischer and former Library of Natural Sounds associate, Ted Parker, were huge sources of inspiration and encouragement.

        For providing periodic financial support, we sincerely thank WINGS, Inc. We would also like to thank the Cape May Bird Observatory for use of their library and for their encouragement.

        For answering queries, providing research materials, or various other forms of assistance or encouragement, we thank John Arvin, Parker Backstrom, Carol Belser, Louis Bevier, Rick Blom, Ned Brinkley, Betsy Brooks, Danielle Callahan, Claudette Cormier, Richard Crossley, Dave Czaplak, Ken DeSmet, Jim Dowdell, Kathy Duffy, Jon Dunn, Pete Dunne, Kim Eckert, Karen Edelstein, Vince Elia, Dave Evans, Andy Farnsworth, Judy Fieth, Shawneen Finnegan, Annette Finney, John Fitzpatrick, Joan Fowler, Kimball Garrett, Sid Gauthreaux, Jean Graber, Bernie Guirey, Cullen Hanks, Meena Haribal, Dave Hedeen, Mark Hoffman, Steve Howell, John Huehnergard, Ottavio Janni, Kevin Karlson, Ken Kaufman, Paul Kerlinger, Clarence and Margaret Klingensmith & family, Ron Larkin, Paul Lehman, Tony Leukering, Michael Male, Joe Marshall, Rhonda Millikin, David Mizrahi, Frank Nicoletti, Evan Obercian, John O’Brien, Paul O’Brien, Henri Ouellet, Ted Parker, Paul Pisano, Bill Pranty, Gary Rosenberg, Ken Rosenberg, Will Russell, Deborah Sam, Matt Sarver, Scott Seltman, David Sibley, Rebecca Scholl, Miranda Strichartz, Dick Walton, Hal Wierenga, Chris Wood, and Louise Zemaitis.

        We thank Jessie Barry (back cover art) and Evan Obercian (species page art) for the fine drawings of birds in flight included in this CD-ROM. We thank Volker Dierschke for the opening page photo (non-html edition) of us recording migrants with shotgun microphones in the dunes of Cape May, NJ, and Dick Graber for permission to use the picture of him with the parabolic dish recording apparatus on the inside of the CD-ROM jacket.

        Most of all, we wish to thank our dads, William E. Evans and Paul J. O’Brien, whose interest in birds was lovingly passed on to us and who first turned our attention to night flight calls of migrating birds. And, for their endless support, we also thank Karen Bills, Cynthia L. Fleming & family, Barbara O'Brien, John O'Brien, Alec Smith, Bradley Smith, and Louise Zemaitis.