copper bone
...Wildebeests, Gemsbok, Kudu and Springbok. It's kinda cartoonishly silly that even on Hunter difficulty, you can spot them 6-800 yards, then walk normally to the distance you need to view them in Hunter sense.
These are plains animals adapted to their environment. One of those adaptations is really good long range vision.
300 yards (or meters) sounds like a reasonable standing spook distance
dire fox