Located in the center of Big Bend NP are the Chisos mountains, which form a vista-filled basin of high mountains, valleys, and breathtaking wildlife. Casa Grande is closed to hikers for the benefit of peregrine falcon nesting. Golden eagles scream at hikers (me & colleagues) on the top of Lost Mine Peak (elevation: 7,750 feet). And the Chisos are hardly alone for company in the mountainous area of southwest Texas.