California Department of Fish and Wildlife, 2022, Winter Ranges of Mule Deer in the Modoc Interstate Herd in California, in Kauffman, M.J., Lowrey, B., Beck, J., Berg, J., Bergen, S., Berger, J., Cain, J., Dewey, S., Diamond, J., Duvuvuei, O., Fattebert, J., Gagnon, J., Garcia, J., Greenspan, E., Hall, E., Harper, G., Harter, S., Hersey, K., Hnilicka, P., Hurley, M., Knox, L., Lawson, A., Maichak, E., Meacham, J., Merkle, J., Middleton, A., Olson, D., Olson, L., Reddell, C., Robb, B., Rozman, G., Sawyer, H., Schroeder, C., Scurlock, B., Short, J., Sprague, S., Steingisser, A., and Tatman, N., 2022, Ungulate Migrations of the Western United States, Volume 2: U.S. Geological Survey data release, https://doi.org/10.5066/P9TKA3L8.
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, oil and gas 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. This second volume describes an additional 65 migrations mapped within nine western states and select tribal lands. 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 and federal stakeholders to reduce barriers to migration caused by fences, roads, and other development.
