When you're walking in the woods with your camera looking for wildlife to shoot, sometimes they see you before you see them (or smell you or hear you). You have to look for the little something that isn't quite right. Sometimes it's a small movement, a flick of the ear or chewing of grass. Sometimes it's a couple of inches of antler tine.
Here I've seen this cow elk before she's seen me. It's just her head but that's enough. She is with a herd and I don't know where all of them are. That's the hard part, sneaking up on a group of animals because of all the eyes on the lookout.
So I try to get into a better position and move a little closer and...
I didn't see these two and now I'm caught.
They're not spooked as my movements were slow enough and the wind is in my favor so they can't smell me but they know something is wrong.
the bark of shame!
Yes, when an elk spots you but doesn't know what you are yet, they let out a loud, dog/pig/tyrannisorusRex-like bark telling everything else in the forest that something, probably dangerous, is close by. They'll do it over and over again and good luck trying to blend in with your surroundings as it will be quite some time before the forest calms down enough and stops staring at you.