<< What I don’t understand is the Desert Tortoise being endangered by cattle on a wide open desert >>
Cows improve the habitat for the tortoise by breaking crusted soils and fertilizing them. That promotes the growth of grasses and forbs that he tortoise needs for food.
The biggest problem for the tortoise is that ravens and crows eat their young, about which the BLM does very little.
http://www.freerepublic.com/focus/news/3143808/posts?page=54#54
I was thinking about ravens and crows, also hawks and eagles could attack the older turtles by catching them, fly up and drop them on some rocks to open them up to eat. I guess the BLM had better start killing these birds of pray to protect the turtles.