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The project leads for the collection of this data were Erin Nigon and Michael Hunnicutt. The East Shasta Valley sub-herd of Rocky Mountain elk (Cervus canadensis nelsoni) range as far east as the eastern foothills of Shasta Valley, as far north as the Klamath River, and as far south and east as Deer Mountain. In the winter, these elk spend most of their time on private ranchlands in Shasta Valley. This area offers patches of oak woodlands and grasslands on gentle slopes. In the spring, elk migrate to their summer range around Grass Lake, Bull Meadows, and Deer Mountain where the habitat is primarily characterized by mixed conifer timber stands of Ponderosa pine (Pinus ponderosa), lodgepole pine (Pinus contorta) and Douglas fir (Pseudotsuga menziesii). The meadows around Grass Lake seem especially important to this sub-herd, as neonatal calves have been documented in this area since at least 1984 (Fischer 1987). Some animals from this sub-herd have moved into Oregon periodically, while others have moved long distances eastward to other sub-herds, but Highway 97 presents a significant barrier to this movement. Most elk mortality due to vehicle collisions on Highway 97 has been documented to occur between Horsethief Creek, and Grass Lake Summit (California Department of Transportation, unpublished data). Because of this, a wildlife crossing is proposed for this area to promote habitat connectivity and wildlife movement. Elk (5 adult females, 5 juvenile [less than 1 year of age] males, and 8 juvenile females) were captured from 2016 to 2020 and equipped with Lotek satellite GPS collars. Additional GPS data was collected from elk (7 females and 1 male) in 1999-2001 and included in the analysis to supplement the small sample size of the 2016-2020 dataset. GPS locations were fixed at 4-hour intervals in the 2016-2020 dataset and 3 to 8-hour intervals in the 1999-2001 dataset.
Migration lines as symbolized connect GPS data points per elk per seasonal migration. GPS points were extracted only during migrations using net-squared displacement graphs. Fifty-one migration sequences from 10 elk, with an average migration time of 4.87 days and an average migration distance of 22.14 km, were used from the 2016-2020 dataset. Fourteen migration sequences from 8 elk, with an average migration time of 7.43 days and an average migration distance of 30.08 km, were used from the 1999-2001 dataset. Average migration distance and time were higher in 1999-2001 dataset due to a single male elk outlier; removing this outlier led to a mean migration distance of 20.36 km and a mean migration time of 5.75 days for the 1999-2001 dataset.