Until recently, knowledge of the migratory movements of small birds was based only on idiosyncratic band returns and inferences from biomarkers and population demographics. Although researchers have been able to track large birds for decades using various electronic devices, traditional long-distance tracking methods, such as satellite telemetry, employ tags that are far too large for the majority of bird species (those weighting 20 grams or less). However, a new tool has emerged that can revolutionize our understanding of bird migration. Solar-geolocation data loggers, or geologgers, are extremely small and simple tracking devices that store light-intensity readings at regular intervals for determining both day length, which indicates latitude, and the time of solar noon, which indicates longitude. Geologgers have recently been deployed on several small bird species and the success of these early studies has sparked considerable interest in these devices among scientists and bird enthusiasts. Although geologgers are already yielding exciting results, there is a need to improve the instrumentation (both hardware and software), establish guidelines for the use of geologgers, and increase their accessibility to the scientific community. A major goal of this project is to improve upon an existing geologger design to create a device that can be deployed in large numbers on a wide range of species by virtually any research group or institution. A second goal is to generate sophisticated yet accessible analysis tools that incorporate multiple sources of information into a Bayesian framework for generating the best possible estimates of migration tracks. Specifically this project seeks to: 1) reduce the size of geologger hardware; 2) repackage an underused but powerful analysis package (tripEstimation) for processing geologger data; 3) increase the availability of geologgers by offering assembled units, electronic kits, and do-it-yourself instructions; 4) carry out extensive field testing and analyses to evaluate the accuracy of the devices and their effects on bird behavior; and 5) reduce the cost of geologgers by an order of magnitude.
Making geologgers available to large-scale banding operations and researchers with limited funds will promote a tremendous scientific advance that will reverberate across numerous disciplines. As information from multiple tracking efforts is synthesized, researchers will be able to establish connectivity maps linking breeding and wintering areas used by different populations of migratory birds. These activities will enable comprehensive conservation strategies that can identify critical habitats for migratory birds and protect vulnerable species throughout their annual cycles. To help ensure that this sort of data synthesis is possible, the geologger software resulting from this project will be implemented through Movebank.org, an online repository for storing and distributing animal tracking data. Scientists who use Movebank.org will contribute to a resource used by students and researchers worldwide ranging from professional wildlife biologists seeking to advance evolutionary theory to grade-school children working on science fair projects. Tracking animals with geologgers requires a synthesis of biology, earth science, electrical engineering, and mathematics. As such, geologger studies are excellent material for addressing STEM (Science, Technology, Engineering, and Math) learning objectives. Working through The University of Oklahoma K20, a collaborative group of project personnel and schoolteachers will generate lesson plans for K-12 students based on the concept of solar geolocation and the construction of microprocessor-based data loggers. These lesson plans will reach teachers across the US and abroad through the K20alt website, maintained by the K20 Center.
