Use a small, low‑profile sensor kit that can record movement and heat signatures. Hide it in a rock crevice where the patrol will pass, and set it to trigger only when a body crosses a certain line—no visible trail, no noise. Then cross the ridge yourself at night, following the exact same path but at a different time; you’ll pick up the same footprints and get a clear picture of the new pattern. Keep your own tracks minimal by staying on the same paths and covering them with natural debris when you return.