Inferring environmental drivers of animal migration path choice


Zijian Wan1, Somayeh Dodge1, Gil Bohrer2

1Department of Geography, University of California Santa Barbara, USA 1Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, USA


Migration enables animals to exploit spatially discrete habitats to accomplish various biological objectives (e.g., breeding, reproduction). During migration, animals respond to environmental variation by altering their path choice. We develop a trajectory-similarity-based hierarchical clustering framework to evaluate variability in movement patterns of migratory birds. The proposed framework leverages trajectory-similarity analysis to reveal the relationships between migration paths and the underlying environmental factors influencing movement choices of migratory turkey vultures (Cathartes aura) in North America. Multiple commonly used trajectory-similarity measures are integrated using a hierarchical clustering approach. These include Fréchet distance, dynamic time warping (DTW), Hausdorff distance, longest common subsequence (LCSS), and normalized weighted edit distance (NWED). From tracking data of 13 turkey vultures during their migration seasons between 2005 and 2020, fall and spring migration clusters are identified. Using trajectory annotation with Movebank EnvDATA, we characterize the obtained clusters based on the environmental conditions that were “used” by the turkey vultures at recorded track points. Environmental factors considered in this study include thermal uplift, air temperature, vegetation greenness, orographic uplift, wind patterns, and precipitation. We contrast the characteristics of the clusters against the background distribution of the same environmental factors (i.e., the “available” conditions). The outcome suggests that except for orographic uplift, all other aforementioned environmental factors seem to contribute to turkey vultures’ migration-path choice. In addition, different preferences are manifested among clusters even for the same factor. The proposed framework can be applied to analyze movement paths of any migratory species.


Movement ecology; trajectory similarity; avian migration; GPS trajectories; environmental conditions

Session info

Session title: Animals and their use of space

Session organizers: Claire Burch, University of Oklahoma, Norman, OK Rebecca Loraamm, University of Oklahoma, Norman, OK

Session sponsors: Animal Geographies Specialty Group Applied Geography Specialty Group Environmental Perception and Behavioral Geography Specialty Group

In this session, we invite papers examining questions of animal space use towards new ecological, biological or conservation knowledge. Included are studies dealing with themes such as animal movement, space use as adaptation, habitat selection, home range delineation, migration, territoriality, gene dispersal, group movement dynamics and site fidelity. Completed and ongoing studies, be they quantitative or qualitative in their methodology, are welcome. In addition to quantitative and qualitative evaluations of animal movement and use of space-oriented around wildlife, we hope to bring human perspective and interactions to this discussion. We are also interested in seeing research that evaluates animal use of space with a human component, including topics such as human perception of animal migration and movement, animal movement and use of space in urban areas and interactions with human space, and other related topics that integrate how humans share space with animals. Past iterations of this session have led to vibrant discussions accompanied by a diverse representation of geographic, ecological, and biological perspectives.