Ostrich-horse is a good description for whatever the animal is that's making those noises. Clint's just trying to get a feel for things however he can without actually making use of the data point. As one could imagine, it's not going so well, because nothing he's seen as far as plant life is actually familiar. He just can't shake the thought that he doesn't want anyone else messing with his head.

He looks up when he hears Katara calling to him, and he can't help but smile at the sight of the younger girl approaching. "Yeah, I saw them. Kind of neat, huh? I have no idea what any of them are, but I know of at least one person around here who does."