Trav's readings aren't terribly easy for her to interpret. She did get some low-output power sources registering in the area from the TARDIS, but she hadn't been able to pinpoint them very well. Perhaps talking with the locals will lead to some other ideas.
As Trav starts to make her way down the hill, the big herd animals are the first to react,and they do it with a set of raucous honks as they shy away from Trav's approach. The mounted riders are the first to react, sending up some more of the horn-calls that the group heard earlier. Three of them rein their lanky mounts in Trav's direction, with their lances leveled toward her, though they're merely approaching at a cautious trot, not charging her.
As they come closer to her, she can see that they're wearing beaten metal masks as well as their shining bangles, and they and look something like this:
As the big animals amble away from Trav, she sees that several individuals on foot are walking out in the direction of those creatures, and those have a different appearance:
As the masked riders come nearer, they look at each other.
"What iss it?" one asks the others. "Have you sseen the likess of these creaturess before?"