3.7.2.3 Rare, Threatened, and Endangered Wildlife Species

travel is unlikely to directly affect nesting or migrating birds, but dust may be an issue from approximately June through August. The Erosion and Sediment Control Plan will address practices to be established during Project construction and operation to minimize the potential for generating windblown dust from Project activities and to control fugitive dust. These measures will reduce fugitive dust emissions that could disturb nesting birds and affect habitat and forage quality.

Transmission lines can cause mortality of raptors, waterfowl, and migratory birds through direct collision or electrocution. Collision tends to affect birds that are migrating through the area and are unfamiliar with the location of wires. Electrocution tends to affect larger birds such as raptors, which, upon landing or taking flight, ground the live wires and connect the circuit. Electrocution or collision could cause injury or mortality to birds; for instance, red-tailed hawks are the most-reported hawk mortalities from collisions with powerlines (Manville 2002). Mortality as a result of collision with transmission structures or lines will be greatest where the movements of migrating birds are the most concentrated.

Two potential areas of concern will be where the proposed transmission line crosses Troublesome and Difficulty Creeks. These crossings could represent a risk to waterfowl because of the presence of wetlands/riparian habitat and agricultural fields abutting these areas. These areas were highlighted because of their potential use by waterfowl, but other types of birds could also be affected by collision with the proposed transmission line structures, conductors, or static wires. Black Canyon will design transmission structures and wires in accordance with applicable APLIC guidelines to minimize the threat to avian species. Black Canyon proposes to conduct pre-construction surveys to document any raptors and nests that occur in the Project vicinity. Also, appropriate temporal and spatial buffers will be implemented in consultation with relevant state and federal agencies.

3.7.2.3 Rare, Threatened, and Endangered Wildlife Species Insects

Based on Black Canyon’s botanical and wildlife habitat surveys of the wildlife study area and the analysis in Appendix G, there is a very low potential for milkweed to occur in the footprint of the upper reservoir and therefore be removed. It is highly unlikely that any monarch butterfly individuals would be inundated. No monarch butterflies were observed during the wildlife habitat surveys, and the vegetation surveys did not identify milkweed. However, both showy milkweed and pallid milkweed could occur in the study area. Therefore, prior to construction, Black Canyon will conduct a survey and habitat assessment in areas where milkweed is most likely to occur (i.e., wetlands, roadsides, drainages, mesic areas) for suitable monarch butterfly habitat. If suitable habitat is identified in an area of proposed disturbance, Black Canyon will discuss avoidance or mitigation measures with the FWS. In addition, as described in Section 3.6.4, as appropriate, milkweed species will be included in the native seed mixes specified in the Habitat Restoration, Reclamation, and Enhancement Plan to improve habitat for the monarch butterfly. Black Canyon will also incorporate the following measures to benefit pollinators, including the monarch butterfly:

• During operation of the Project, Black Canyon will adjust timing of vegetation management in areas containing plants used by monarchs to not interfere with monarch breeding or sources of nectar used as a food source along the migration route. This will be included in the Habitat Restoration, Reclamation, and Enhancement

Plan. • Black Canyon will work to eliminate or reduce the use of insecticides, which can result in direct mortality to monarchs. The use of pesticides including herbicides will be described in Black Canyon’s Noxious Weed Management Plan.

Birds

Federal and state-listed birds for which there is suitable habitat within the Project vicinity are identified above in Table 3.7-5. As previously mentioned, bald eagle and golden eagle presence in the wildlife study area have been directly observed (HDR 2022c). Based on the results of the raptor nest surveys (HDR 2022c), one active bald eagle nest was observed in the wildlife study area in 2021. Construction noise or activity during the nesting season could contribute to nest abandonment and failure. Both breeding and wintering bald and golden eagles could be susceptible to injury or mortality from transmission line collision. Golden eagles exhibit lower tolerance to disturbance compared to bald eagles (USFWS 2007). The potential impacts on the golden eagle are the removal of foraging habitat in the upper reservoir, potential impact on nesting, and potentially forcing intra- and interspecific competition for territories and prey.

Construction of the proposed Project may displace federal and state-listed birds. If construction activity starts after birds have begun nesting, nests may be abandoned or destroyed. Excavation, road improvements, and other vegetation-clearing activities can be timed to minimize disturbance to nesting birds. Protection and mitigation measures for birds are detailed in Section 3.7.4.

Greater Sage-grouse

Greater Sage-grouse were observed at five lek locations at least once during the lek monitoring in 2021 and 2022. No recorded leks are located near the upper reservoir area. Occupied leks are primarily adjacent to the proposed transmission line.

Greater Sage-grouse may be temporarily disturbed due to noise and increased human presence, noise during construction activities, and an increase of vehicle travel on access roads. However, these disturbances will not occur during lekking, nesting, or broodrearing, due to WGFD and BLM surface use restrictions. Some construction activities can be timed to minimize impacts, but loss of habitat from Project construction and operation may displace Greater Sage-grouse. The presence of additional transmission lines will increase perching opportunities for avian predators which may in turn result in increased predation on Greater Sage-grouse.

Based on the proximity analysis, primary facilities that may be visible from the seven occupied leks closest to the Project include portions of the access road along the existing transmission line and the proposed transmission lines. As mentioned above, the proposed transmission lines will parallel two existing transmission lines as well as either existing

county roads or two-track ranch roads. Therefore, the proposed transmission lines are qualitatively expected to only minimally alter the lek viewsheds in the study area (HDR 2022e). In addition, Black Canyon proposes to engineer the height and number of tall structures at the upper reservoir during design to reduce potential impacts.

The Project is located partially within a Greater Sage-grouse Core Population Area and, therefore, Black Canyon will submit its Project footprint for WGFD review through the DDCT process. The estimate of the total debits resulting from direct and indirect impacts of the Project will be calculated for the Project following final design. If determined necessary, Black Canyon will develop a mitigation plan in coordination with the WGFD (HDR 2022e).

Mammals

The swift fox is a Wyoming BLM Sensitive Species and a WGFD SGCN Tier II species. Although swift foxes were not observed during the 2021 wildlife field surveys, the WYNDD (2021) includes observations in the vicinity of Difficulty Creek and Medicine Bow, on the eastern edge of the wildlife study area (HDR 2022c). Direct mortality can occur by destruction of occupied burrows or dens during vegetation clearing, excavation, and grading, or by collision with vehicles on roads to and from the Project.

The white-tailed prairie dog is a Wyoming BLM Sensitive Species and a WGFD SGCN Tier II species. White-tailed prairie dogs were observed during the 2021 wildlife field surveys, and they are relatively common within suitable habitat of the wildlife study area (HDR 2022c). Excavation could injure individuals in burrows. There is abundant habitat for white-tailed prairie dog elsewhere in the Project vicinity. Given adequate protection and mitigation measures, no Project-related effects are anticipated on white-tailed prairie dog populations in the Project vicinity.

The northern river otter is a WGFD SGCN Tier II species. No river otters were observed during the 2021 wildlife field surveys. The WYNDD (2021) does have a record of an otter sighting from the 1980s in an inlet on the west side of Seminoe Reservoir; however, no observations have been recorded within the study area (HDR 2022c). Considering there is minimal aquatic habitat present in the wildlife study area that will be impacted as a result of the Project, no Project-related effects are anticipated on river otter populations in the Project vicinity.

The pygmy rabbit is a Wyoming BLM Sensitive Species and a WGFD SGCN Tier II species. Pygmy rabbits were not observed in the wildlife study area during the 2021 wildlife field surveys and there are no records of observations in the vicinity of the wildlife study area (WYNDD 2021). Range mapping by WYNDD and WGFD do not include the wildlife study area and most of Carbon County is extralimital for the species. While it is unlikely that pygmy rabbits occur in the wildlife study area, there is suitable habitat present (HDR 2022c). Direct mortality can occur by destruction of occupied burrows during vegetation clearing, excavation, and grading, or by collision with vehicles on roads to and from the Project.

The Wyoming pocket gopher is a Wyoming BLM Sensitive Species and a WGFD SGCN Tier I species. Wyoming pocket gophers were not observed during the 2021 wildlife field surveys. The WYNDD (2021) does not include any observations of the species in or near the wildlife study area. The nearest recorded observation is southwest of the wildlife study area, near Haystack Mountain (HDR 2022c). Excavation could injure individuals in burrows. Given adequate PM&E measures, no Project-related effects are anticipated on Wyoming pocket gopher populations in the Project vicinity.

There are five special-status species of bats with the potential to occur in the wildlife study area (HDR 2022c). Most of the bat species listed in Table 3.7-5 are either WGFD protected or sensitive species and/or BLM sensitive species. Bats are prone to many of the same threats as avian species, including collision-related injuries and mortalities. Black Canyon’s proposals to minimize outdoor lighting are expected to limit Project effects on bats and reduce disruption of nocturnal activities.

Amphibians

The Great Basin spadefoot is a BLM Sensitive Species and a WGFD SGCN Tier II species. The Great Basin spadefoot was not observed during the 2021 wildlife field surveys. The WYNDD (2021) includes recorded observations from the western Seminoe Mountains and eastern Ferris Mountains located outside the wildlife study area. The WYNDD species distribution model (WYNDD 2010) does not include the wildlife study area, but WYNDD’s range map for this species includes the north slope of the Seminoe Mountains within the wildlife study area (WYNDD 2021). The GAP species analysis program maps potential distribution of the species throughout the entire wildlife study area (USGS 2017). Based on this information, Great Basin spadefoot are likely very rare in the wildlife study area, but they could occur throughout most landcover types. Breeding habitat is more restricted to areas with reliable water sources (HDR 2022c). Incidental direct and indirect impacts to Great Basin spadefoot, such as collisions of slow-moving individuals with vehicles or equipment, could occur during Project construction and operations.

The northern leopard frog is listed as a Wyoming BLM Sensitive Species and WGFD SGCN Tier II species. No northern leopard frogs were observed during the 2021 wildlife field surveys. The WYNDD (2021) lists two observations of northern leopard frog in the study area at Seminoe Reservoir and along the North Platte River from before 1980. More recent observations have been recorded in the general area, outside of the wildlife study area. Because this species is widespread, relatively common, and occurs in a broad range of aquatic environments, it is expected to occur in the wildlife study area. Northern leopard frog habitat is not expected to be directly affected by the proposed Project because of the abundance of their available habitat in Wyoming. Incidental direct and indirect impacts to northern leopard frog, such as collisions of slow-moving individuals with vehicles or equipment, may occur during Project construction and operations.