Advocates who back the idea of wild horses roaming free in the West are challenging the most recent roundups of mustangs, which began Monday in northwest Colorado. Habitat for Horses claims the U.S. Bureau of Land Management “intends to simply eliminate this herd for its convenience” (via Courthouse News Service). The group is joined in its suit by the American Society for the Prevention of Cruelty to Animals and the Cloud Formation, among others, which all say the wild horses, once captured, will “languish in inadequate long-term holding for the rest of their lives.”

Despite the legal action, BLM helicopters began to wrangle about 140 horses that have moved beyond the public lands set aside for them, writes The Associated Press.

A BLM website is tracking the progress of the roundup and reports that 13 animals have been herded so far with no deaths.