ThruTracker: Open-Source Software for 2-D and 3-D Animal Video Tracking
O_LITracking animal movement patterns using videography is an important tool in many biological disciplines ranging from biomechanics to conservation. Reduced costs of technology such as thermal videography and unmanned aerial vehicles has made video-based animal tracking more accessible, however existing software for processing acquired video limits the application of these methods. C_LIO_LIHere, we present a novel software program for high-throughput 2-D and 3-D animal tracking. ThruTracker provides tools to allow video tracking under a variety of conditions with minimal technical expertise or coding background and without the need for paid licenses. Notable capabilities include calibrating the intrinsic properties of thermal cameras; tracking and counting hundreds of animals at a time; and the ability to make 3-D calibrations without dedicated calibration objects. Automated 2-D and 3-D workflows are integrated to allow for analysis of largescale datasets. C_LIO_LIWe tested ThruTracker with two case studies. The 2-D workflow is demonstrated by counting bats emerging from bridges and caves using thermal Videography. Tests show that ThruTracker has a similar accuracy compared to humans under a variety of conditions. The 3-D workflow is shown for making accurate calibrations for tracking bats and birds at wind turbines using only the wind turbine itself as a calibration object. C_LIO_LIThruTracker is a robust software program for tracking moving animals in 2-D and 3-D. Major applications include counting animals such as bats, birds, and fish that form large aggregations, and documenting movement trajectories over medium spatial scales ([~]100,000 m3). When combined with emerging technologies, we expect videographic techniques to continue to see widespread adoption for an increasing range of biological applications. C_LI