In 2013, a section of Montana Highway 200 (MT Hwy 200) east of Thompson Falls, Montana was scheduled for road reconstruction. Bighorn sheep (Ovis canadensis) cross and spend time on and adjacent to this section of MT Hwy 200 . The bighorn sheep appear to be primarily interested in licking salt off the road surface and are frequently hit by vehicles. This direct mortality was believed to be among the primary causes for the substantial decline of the local population of bighorn sheep that had been observed in recent years.
The section of MT Hwy 200 between mile reference posts 55.9 and 59.1 (project names TR-E bridge and approach; E-TR-E) was scheduled for reconstruction and wildlife mitigation measures including wildlife fencing and wildlife crossing structures were under consideration. These measures were aimed at reducing collisions with large wild mammals, especially with bighorn sheep, and providing safe crossing opportunities for wildlife.
This project aimed to:
1. Summarize the existing site conditions, wildlife-vehicle collisions, and wildlife movements in the area – with an emphasis on bighorn sheep – based on existing information.
2. Review the mitigation measures proposed by the Montana Department of Transportation and suggest potential modifications to these mitigation measures based on the available information.