If you were sending scouts into uncharted lands, checking the entrails of birds could tell you a lot of information about the local area. Just shoot a bird down with an arrow and cut it open. Are the birds healthy and well fed? if so, there’s signs that the local ecosystem has enough food to perhaps support the movement of your army. Is the bird diseased? Maybe there’s something in the water.

It’s not foolproof, but it was possible to gain actually useful information this way, especially about famine or disease - whereas most other forms of fortune telling are just nonsense.