INTRODUCTION
What defines a species? How do the traits we observe today reflect evolutionary history and environment? Using video and audio recordings of animal behavior, students in a variety of courses can pose questions like these and gather data from diverse species and locations to test their hypotheses. Such recordings are freely available online in the Macaulay Library (http://macaulaylibrary.org), the world’s largest scientifically curated archive of natural history media (3, 6). Managed by the Cornell Lab of Ornithology, the Macaulay Library currently houses about 50,000 video clips and 123,300 audio recordings (including the sounds of 75 percent of the world’s bird species, and recordings dating back to 1929). This article, aimed at faculty teaching biology and environmental science courses, summarizes how to search the online archive and visualize streaming sound files with Raven Viewer. It also describes how instructors have used these tools in introductory and upper-level laboratory and lecture classes as part of the NSF-funded Online Research in Biology project (http://birds.cornell.edu/orb).
PROCEDURE
Navigating the site
The 2011 launch of a new interface greatly improved Macaulay Library’s usability for students in search of recordings from a wide diversity of taxa (insects, fish, amphibians and reptiles, birds, and underwater and terrestrial mammals). The front page has featured recordings and staff picks to browse, or users can enter the common or scientific name of a species in the search bar. As a user begins to enter criteria, the power search initiates and actively makes suggestions in a dropdown menu. Other ways to search include browsing by taxonomy (under “Find” in the menu) or clicking the plus sign (“+”) to conduct advanced searches by location, age, sex, recordist, or behavior (see Fig. 1).
FIGURE 1.
The front page of the Macaulay Library after pressing the “+” button for advanced search options. As well as facilitating searches by location, age, sex, or behavior, advanced search allows the user to find three specific types of recordings: 1) Environmental (ambient soundscapes or scenic vistas); 2) Effects (e.g., feet crunching snow, thunder); and 3) People (including a large number of archived scientist interviews from the joint NPR and National Geographic program Radio Expeditions).
From the search results page, it is easy to toggle between audio and video recordings, and to view video results either as a list or thumbnail images. The user may sort recordings by features such as quality, date, or length. Upon choosing a catalog number, an asset page appears with detailed annotations including recording equipment used and notes about the behaviors or interactions in the clip. Curatorial staff has authenticated all species identifications, and latitude and longitude coordinates have been provided when possible.
Raven Viewer, a free QuickTime plug-in, enables students to visually analyze the frequency, amplitude, and duration of sounds in real time as the recordings play. The spectrogram view is particularly helpful in analysis, plotting frequency against time, while showing relative amplitude through line thickness or color. While many technical works on sound visualization and analysis exist, for a first introduction to looking at spectrograms (or sonograms), we recommend the accessible works listed in the references noted here (4, 1, 2, 5).
Integrating the site into lessons
Our primary objective is to encourage use of the Macaulay Library as a source of raw data for student-designed inquiries. These activities can range in timescale from a few minutes of group work during lecture, to a more investigative project lasting one or several lab periods. Below, we highlight examples of how the Macaulay Library has been used both to teach science content and to develop student research skills.
During the lesson “Species Concepts in Birds,” the instructor introduces species concepts in lecture using examples and discussion questions, then uses selected videos from the Macaulay Library to pique student interest in understanding whether Eastern and Western Meadowlarks and Blue-winged and Golden-winged Warblers are truly reproductively isolated. General Biology instructors at Western Connecticut State University followed this with a guided inquiry in lab, during which student pairs tested their hypotheses about potential behavioral reproductive isolation by observing plumage and analyzing song spectrograms. A Tompkins Cortland Community College professor expanded this lesson for his Introductory Biology course by debating the conservation implications of species concepts, and assigning formal lab reports including statistics and graphs.
The open inquiry module, “Why Do Animals Sound Like They Do?” was adapted for the goals and settings of two Ithaca College courses, both of which emphasized scientific research skills. An Animal Behavior professor used a three-hour lab period to brainstorm about factors that might influence animal sounds (body size, habitat, social context), and then introduced basics of sound visualization and resources available in the Macaulay Library (Fig. 2). Students used the remainder of the lab period to formulate research questions in pairs and begin collecting data, before writing individual formal reports as homework. An Ornithology instructor prepared both majors and nonmajors students to conduct multiweek independent projects by introducing sound analysis through guided inquiry done in lab pairs, followed by large group demonstration and discussion of the Macaulay Library as a source of research data. Students peer-reviewed one another’s ideas in lecture, then spent several lab periods doing independent research before final oral presentations and written report submissions.
FIGURE 2.
Ithaca College students use the Macaulay Library to design their own investigations on variation in animal sounds as part of an Animal Behavior lab section. The “at-a-glance” guide to Raven Viewer pictured can be found on the Online Research in Biology website (http://birds.cornell.edu/orb). Instructors may wish to ask the students to bring headphones or earbuds, and may want to provide alcohol wipes or splitters for sharing headphones.
Practicalities
The Macaulay Library’s online archive serves as a useful tool for students and faculty to locate and easily link to high-quality examples of animal sounds and behaviors from around the globe. However, there are some cases where instructors may want to prepare for using the archive in advance, or download more detailed help sheets and implementation suggestions (http://birds.cornell.edu/orb). If the search menu or taxonomy browser indicates a large number of recordings for the species or taxa being studied, instructors should decide whether to select a few prime examples for students to use (sorting by the “Quality” field), or else use this as a teachable moment on sampling methods for research. If the examples desired are not available, alternative archives with slightly different areas of geographic emphasis include Xeno-Canto (http://www.xeno-canto.org/) and Wild Sanctuary (http://www.wildsanctuary.com/) for sounds, and ARKive (http://arkive.org) and the BBC Motion Gallery (http://www.bbcmotiongallery.com/) for videos.
Access to Macaulay Library recordings is through streaming Flash files. Additionally, to view sound visualizations with Raven Viewer, both QuickTime and a custom plug-in must be installed, so technical support may be needed to install these on every computer in a lab. Strategies for dealing with these issues include asking students to use their own laptops, or ordering downloadable files in advance from the Macaulay Library (http://macaulaylibrary.org/guides and http://macaulaylibrary.org/order), and using them with the free desktop software Raven Lite (http://RavenSoundSoftware.com), if live Internet connectivity will not be possible.
CONCLUSION
Rich media examples bring to life the discussion of an anatomical feature, how a grouping or feeding behavior might predispose an animal to disease transmission, or how phenotypic traits vary within and across groups of closely related animals. However, online archives may also be used to address other learning objectives. Follow-up surveys with eight faculty piloters indicate science process skills were the most highly desired student outcome, followed by knowledge of science content. Macaulay Library investigations were deemed moderately or highly successful in these areas, with greatest success in raising awareness of the growing role of the Internet in scientific research and the variety of data sources and media types used. Student surveys also appear to show expanded awareness of the nature of modern e-science after investigating species concepts in the Macaulay Library. Important things learned by an Introductory Biology student and an Ornithology student were that, “Having a repository for collecting and storing data is key to effective collaboration among scientists,” and “A surprisingly wide variety of questions can be investigated through database research.”
ACKNOWLEDGMENTS
This material is based upon work supported by the National Science Foundation under Grant No. 0919686. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. We thank Nancy M. Trautmann and Michael S. Webster for providing feedback on an earlier version of this article. The authors declare that there are no conflicts of interest.
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