at the trail—(Military) carrying a rifle in the right hand, the arm at full length, and the gun horizontal:
- The volunteers are in step, rifles are carried uniformly horizontal at the “trail.”
on the trail—
1. following a path in a wild or uninhabited region:
- In discrete valleys were a few cabins, and they stayed in them or siwashed (camped on the trail).
2. following traces or tracks in hunting:
- Jacob’s dog leads them into the woods on the trail of a fox, and there they come upon the wreckage of a small plane.
3. following smb.; in pursuit of a person:
- The police are on the trail of a group of Satanists, believed to have caused a young man’s death.