This collection documents Crawford H. Greenewalt's personal study of ornithology, primarily his work on hummingbirds. The materials date from 1951 to 1993 and are arranged into the following series: "Manuscripts/writing/publications," "Photographs: Proofs and contact sheets," "Photographs: Mounted prints," "Slides and transparencies," "Negatives," "Microscope slides," "Sketches for 1960 publication Hummingbirds," "Awards," and "Objects." The collection consists primarily of photographs taken by Greenewalt and technical data collected by Greenewalt. The images photographed by Greenewalt exist in many different formats throughout the collection, including prints, negatives and slides. The technical data in this collection represents Greenewalt's research into the physiology of hummingbirds, and the development of his high-speed photographic technique. In addition to Greenewalt's research material, this collection also houses drafts and edits of some of Greenewalt's original publications.

Photographs constitute the bulk of this collection, most of which are undated. When there are dates associated with an image, it is not certain whether those dates refer to the moment the picture was taken or when the print was created. Greenewalt's field notes are the most promising component of this collection for determining photograph dates. These forty-four notebooks contain documentation of photo sessions between the years 1956 and 1983, including the name of the bird, location and date. Researchers concerned with knowing the exact date of any particular image should consult Greenewalt’s field notes for clues.

This collection is of great research value as it documents the process of innovating high-speed photography techniques, amateur ornithological methodology and Greenewalt's research process. This collection also demonstrates wide-spread recognition that Greenewalt's efforts in ornithology received from contemporary academic and professional institutions.

The "Manuscripts/writing/publications" series dates from 1951 to 1993 and contains Crawford Greenewalt’s research and drafts for his publications. This series is divided into six subseries according to subject: "Photography", "Hummingbird Project", "Feather reflectance", "Flight", "Birdsong," and "Personal papers." Because materials in this series are arranged in a chronological manner, researchers interested in correspondence with specific individuals and/or subjects, should review the entire folder list.

The "Photography" subseries contains material related to Greenewalt's photography experimentation and technique development. The first part of the subseries is a collection of field notebooks, which document Greenewalt’s photographic efforts from 1956 to 1983 and are arranged chronologically. These notebooks document photo shoots, providing information on the location, subject, name, date and technical information about camera setup and use. The second portion of the "Photography" subseries contains Greenewalt's collection of equipment operation manuals and test data. The manuals and the test data associated with the specific pieces of equipment are arranged alphabetically by object name.

The "Hummingbird Project" subseries contains materials related to Greenewalt's publication, Hummingbirds. These materials include inventories of bird photographs and slides, drafts of captions for illustrations, and marked-up proofs of the photos that were used for that monograph. As a whole, this subseries demonstrates Greenewalt's editing process for this project. The materials are arranged chronologically.

The "Feather reflectance" subseries consists almost entirely of technical data and publications that Greenewalt referenced while doing research for his own publication on the physical properties of hummingbird feathers. In addition to this research material, this subseries also contains a group of electron microscope images of hummingbird feathers. The material in this subseries is arranged chronologically.

The "Flight" subseries contains a good deal of technical data related to the physics of bird flight, including notebooks containing flight sketches showing wingtip movement, wingtip movement analysis data, and information about physical proportions. This subseries contains some published material that Greenewalt used for research, as well as drafts and final versions of his own publications on the topic. The materials in this subseries are arranged alphabetically.

The majority of the materials contained in the "Birdsong" subseries is comprised of technical data. Specifically, there are large amounts of harmonic measurements or oscillograms of various bird calls, which Greenewalt has called "birdsong," and writings that analyze and describe these measurements. This subseries also includes phonographic recordings of bird calls and Greenewalt’s published material on the topic. This subseries emphasizes the research aspect of Greenewalt's writing, rather than the editing process. This subseries is arranged chronologically.

The "Personal papers" series contains some correspondence and other personal ephemera.

The "Photographs, proofs and contact sheets" series contains what could be considered rough drafts of the more finished photographic prints that are found in the "Photographs, mounted prints" series. Many of the images in this series appear elsewhere in the collection in various formats. The majority of the photographic prints in this series are undated and the subjects are unidentified. The prints in this series are arranged chronologically, based on dates that are associated with these images either on their original housing or elsewhere in the collection.

The "Photographs, mounted prints" series contains color prints mounted on mat board. There are three sets of prints that are included in this series. Each of the three sets is a different size, and each size constitutes its own subseries. Original order for the entire "Mounted prints" series has been maintained.

The "8 x 10 mounted prints" subseries contains colored prints of a wide variety of birds. The birds are identified on most of the prints. There seems to be two groups of prints in this subseries - those dated 1964, and those dated 1969 to 1971. It is not clear if those dates represent the years the photos were taken, or the years the prints were made. Prints with dates between 1969 and 1971 attributed to them tend to have more information about the subject than do the rest of the prints in this subseries, including species, gender, location and date.

The second subseries, "8.5 x 11 mounted prints," are arranged into six volumes. Identification is inconsistent and less explicit than that provided in the "8 x 10" subseries. Most of the prints provide the species name of the subject.

The "10 x 15 mounted prints" subseries is a twenty one volume set of color prints. The set features hummingbirds almost exclusively, except for the final two volumes which contain many of the same images that appear in the smaller sets. Identification is provided for all but a few of the subjects in this set.

The "Stereographs" subseries contains color, and black and white stereographs of a small variety of birds at different angles. These images have been mounted on mat board cards. Most of the cards in this series are numbered 1 to 579, with large gaps in the 500s. This series also contains a group of unnumbered, unidentified stereographs. Some of the birds represented in this series have been identified. Some of the stereographs have dates marked on them, which are probably the dates that the pictures were taken. All of the cards, with the exception of the few unmarked cards at the end of the series, contain some technical data which seems to relate to some function of the camera during the photograph session. The cards seem to have been organized into groups according to an "M" value, and then numbered sequentially.

The "Slides and transparencies" series contains various images of birds, some of which can be found in other locations in this collection in various formats. This series is divided into four subseries according to subject and /or medium.

The "Slides of Birds of the World" subseries is a large collection of slides which seems to constitute Greenewalt's attempt to fulfill James L. Peters' Check-list of Birds of the World, an adaptation of which can be found in the first series of this collection. The birds are arranged taxonomically by order. There are multiple images of every bird, and each bird is identified.

The "Personal collection" subseries contains sets of photographic slides, which seem to be of a personal nature. The slides portray images from family vacations and wildflowers. Also represented in this subseries are some of Greenewalt's early experiments with time-lapse photography.

The "Transparencies" subseries consists of photograph negatives of birds that Greenewalt photographed in Ecuador. This subseries also includes a set of large glass and plastic transparencies used during the printing of an article about Greenewalt entitled "Bird Watching with an Electronic Eye."

The "Lantern slides" subseries contains two sizes of three distinct sets of images: "Wrens feeding", "Bluebird" and "Slides for high speed camera."

The "Negatives" series contains photographic negatives of many of the prints in this collection. Three pre-arranged groups of negatives have been arranged into three subseries. Original order has been maintained throughout this series.

The negatives in the "Stereographs" subseries have been numbered 1 to 1000. This subseries also contains a small number of identified birds which are: the tree swallow, the house finch, the Australian finch and the cardinal.

The subseries: "Sequence shots of unidentified birds" contains a group of heavily damaged negatives, which are numbered 1-200. The negatives in this subseries have been rehoused and grouped according to their condition.

The "Early high speed photographs of unidentified birds" subseries contains negatives that were formerly housed in eleven booklets that have been numbered. These images seem to date from the early to mid-1950s, and the birds represented in this subseries are unidentified. The negatives in this subseries have been rehoused and grouped according to their condition.

The "Sketches for 1960 publication Hummingbirds" series contains a variety of hand drawn illustrations in various sizes. This set of sketches constitutes the creation and selection process for the illustrations that appear in Greenewalt’s 1960 publication Hummingbirds. Along with the originals, this series also contains illustrations that had not been chosen for publication, including alternate versions and unique images. This series is arranged according to the order in which the illustrations appear in the publication, with works not selected filed at the end of the series. Within this intellectual order, materials are housed appropriately according to their size.

The “Awards” series provides evidence of the wide-spread recognition that Greenewalt received for his work on high-speed bird photography, chemical engineering, and business management. Greenewalt received honorary degrees, certificates, and medals from a variety of academic and trade organizations.

The “Awards” series is divided by medium into two subseries. The first subseries contains diplomas and certificates, as well as programs from events at which Greenewalt was recognized, such as commencements and organizational meetings. The second subseries contains medals, pins, and statuettes.

The “Objects” series contains a few artifacts related to Greenewalt’s work with ornithological photography. There is a metal camera case which contains a camera and various camera accessories. The leather case housed Greenewalt’s camera (which is now part of VIREO’s holdings, along with Greenewalt’s set), and now contains some random parts and stereograph lenses. This series also includes the Greenewalt’s aluminum camera floating action tripod. The fourth item in this series is a leather map case filled with color travel maps of various European territories.

Researchers interested in Greenewalt's publications, photographs, and techniques associated with the high-speed photography of birds will find this collection to be quite valuable. Indeed, this collection documents these subjects and techniques in the grander scheme of 20th century high-speed photography.