Investigation and assembling of experiments and theories to describe the mechanisms that birds use in flight, with particular interest in hummingbirds. Discussion and exchange of views with other scientists, including Dr. Dean Amadon, American Museum of Natural History; Dr. E. Thomas Gilliard, American Museum of Natural History; Dr. Herbert Friedman, Smithsonian Institution; Dr. Vannevar Bush; Dr. Rene H. Miller, MIT; Dr. Robert W. Storer, University of Michigan; Dr. D.B.O. Savile, Plant Research Institute, Ottawa; Andrew J. Berger, University of Michigan; Dr. Kenneth D. Roeder, Tufts University; Frank A. Hartman, The Ohio State University; Charles H. Blake, MIT; Dr. Torkel Weis-Fogh, Harvard University; Dr. Oliver P. Pearson, University of California-Berkeley; Dr. Hans Oehme, Deutsche Akadamie der Wissenschaften zu Berlin; Dr. S. Dillon Ripley, Yale University, Dr. Olavi Sotavalta, Helsinki, Finland; Dr. J.W.S. Pringle, Oxford University; Dr. Erwin Stresemann, Berlin; and Dr. James L.G. Fitzpatrick, Staten Island Community College.

Reprints and reference articles assembled during the course of investigation.

Arrangements to publish a monograph written by Greenewalt. Copy of monograph included. Record of copies requested and sent.

Technical paper by Greenewalt, “High-Speed Moving Pictures of Hummingbirds,” describing tests conducted and data obtained from high-speed photography. Records of loans and uses of high-speed film, “Aerodynamics in Nature.”

Limited correspondence with friends about birds in Africa and in Colorado, expressing Greenewalt's desire to visit these places.

Arrangements for a trip to photograph hummingbirds of the southwest. Includes a map with areas of greatest interest marked. Trip occurred in 1956.

Arrangements for a trip to Panama to photograph hummingbirds at Barro Colorado Island at a Smithsonian Institution research station. Trip completed in 1957. Map of Panama included, also snapshots of Barro Colorado.

Visits to Brazil to photograph hummingbirds in 1956 and 1957. Arrangements, itinerary, and social plans included. Visited Petropolis, Vittorio, and Santa Teresa. Main contact was Dr. Ruschi, who operated a bird sanctuary at Santa Teresa. Detailed description of the trip, written by Mrs. Greenewalt, is included.

Brazilian visits in 1958 as part of a vacation trip and in 1961 on a trip financed by AMNH. While in Brazil, Greenewalt was awarded the John Fritz medal from the Brazilian Academy of Science. Also another AMNH-sponsored trip in 1963. Includes extensive press coverage of this visit at several ceremonial occasions.