California Department of Fish and Wildlife, 2024, California Pronghorn Lassen Migration Routes, in Kauffman, M.J., Lowrey, B., Beaupre, C., Bergen, S., Bergh, S., Blecha, K., Cain, J.W., Carl, P., Casady, D., Class, C., Courtemanch, A., Cowardin, M., Diamond, J., Dugger, K., Duvuvuei, O., Fattebert, J., Ennis, J., Flenner, M., Fort, J., Fralick, G., Freeman, E., Gagnon, J., Garcelon, D., Garrison, K., Gelzer, Greenspan, E., Hinojoza-Rood, V., Hnilicka, P., Holland, A., Hudgens, B., Kroger, B., Lawson, A., McKee, C., McKee, J.L., Merkle, J., Mong, T.W., Nelson, H., Oates, B., Poulin, M.-P., Reddell, C., Riginos, C., Ritson, R., Sawyer, H., Schroeder, C., Shapiro, J., Sprague, S., Steingisser, A., Stephens, S., Stringham, B., Swazo-Hinds, P.R., Tatman, N., Turnock, B., Wallace, C.F., Whittaker, D., Wise, B., Wittmer, H.U., and Wood, E., 2024, Ungulate migrations of the western United States, volume 4: U.S. Geological Survey data release, https://doi.org/10.5066/P9SS9GD9
Migration is widespread across taxonomic groups and increasingly recognized as fundamental to maintaining abundant wildlife populations and communities. Many ungulate herds migrate across the western United States to access food and avoid harsh environmental conditions. With the advent of global positioning system (GPS) collars, researchers can describe and map the year-round movements of ungulates at both large and small spatial scales. The migrations can traverse landscapes that are a mix of different jurisdictional ownership and management. Today, the landscapes that migrating herds traverse are increasingly threatened by fencing, high-traffic roads, energy development, and other types of permanent development. Over the last decade, a model of science-based conservation has emerged in which migration corridors, stopovers, and winter ranges can be mapped in detail, thereby allowing threats and conservation opportunities to be identified and remedied. In 2018, the U.S. Geological Survey (USGS) assembled a Corridor Mapping Team (CMT) to work collaboratively with western states to map migrations of mule deer, elk, and pronghorn. Led by the USGS Wyoming Cooperative Fish and Wildlife Research Unit, the team consists of federal scientists, university researchers, and biologists and analysts from participating state and tribal agencies. The first set of maps described a total of 42 migrations across five western states and was published in 2020 as the first volume of this report series. The second volume described an additional 65 migrations mapped within nine western states and select tribal lands and was published in April, 2022. The third volume described an additional 45 migrations mapped across most western states and select tribal lands. This volume, the forth in the report series, details migrations and seasonal ranges from an additional 31 new herds throughout nine western states. As the American West continues to grow, this report series and the associated map files released on USGS’s ScienceBase will allow for migration maps to be used for conservation planning by a wide array of state, federal and Tribal stakeholders to reduce barriers to migration caused by fences, roads, and other development.
