Summary: These data represent the DWR edited version of statistically based polygons derived from GPS collared data on animals migrating in Utah from 2016 - 2021. The GPS data were analyzed using the Brownian Bridge Movement Model (BBMM), which produced polygons based on an animal’s movement path from data recorded at brief intervals. This model understands that location points are connected to each other in time. Every animal has its own footprint of its migration. Each animal’s averaged footprint is combined into one layer. Corridor level of use types are combined and clipped into one dataset and the level of use is classified:

Low use: 0 - 25% of the population

Medium use: 25 - 75% of the population

High Use: > 75% of the population (after Sawyer and others, 2009)

Stopovers are extracted from the combined footprints and defined as the top 10% of the values. Stopover sites show where the animals spend most of their time during migration, and are likely used as foraging and resting areas. 

References:

Sawyer, H., Kauffman, M. J., Nielson, R. M., & Horne, J. S. (2009). Identifying and prioritizing ungulate migration routes for landscape‐level conservation. Ecological Applications, 19(8), 2016-2025.