Migration Mapper User Guide


Gage Cartographics LLC and The Wyoming Migration Initiative | October 2017



Understanding and mapping where animals go is of utmost importance to wildlife conservation and management. This is particularly important for migratory wildlife as they rely on connected, seasonal habitats. Given increasing levels of energy development and recreation on public lands, sprawling housing development on private lands, and increasing traffic volumes on roadways, the long-term persistence of migration corridors is uncertain. It is known, for example, that development can alter space use on winter range, affect the speed at which animals migrate, force animals to detour from established routes, and in some cases, impede migration altogether.

In 2009, Sawyer and colleagues devised a method for identifying and prioritizing migration corridors, which provided a way forward to begin mapping and conserving ungulate migrations. The methodology involves a brownian bridge movement analysis of GPS collar data collected from individual animals and a prioritization analysis based on the number of animals migrating through specific areas. The framework has been adopted by the Wyoming Migration Initiative (WMI) to develop their migration assessment program, which includes identifying threats and opportunities for conservation along migration corridors. WMI pioneered this approach by assessing the "Red Desert to Hoback" (RDH) mule deer migration, a 150 mile-long corridor that is the longest yet recorded in the Lower 48. The RDH migration assessment has provided a road map for managers and NGOs seeking to sustain this corridor. It has guided the targeting of conservation easements, fence modifications, highway crossing improvement, and land-use planning on BLM lands.

The issue with these methods, however, is that they are computationally intensive, and require coding and analysis skills that are beyond the reach of most biologists and managers. Many agencies have GPS collar datasets of ungulates, and many are currently collecting data. Although these datasets exist, technological barriers have stymied the evaluation and adoption of the new methods that would allow any manager or biologist to identify, assess, and prioritize movement corridors and seasonal ranges in a consistent way.

The goal of Migration Mapper is to simplify the technologically challenging analyses outlined in Sawyer et al. (2009) into a user-friendly software that can be implemented by biologists and managers using their own GPS collar data. Migration Mapper was not developed to be a ‘pull-the-handle-and-see’ program, but to incorporate information from the user in identifying movement corridors and seasonal ranges. Thus, expect to spend some time working with your data before Migration Mapper spits out a movement corridor map.