I agree with what everyone is saying 100%. I just wanted to touch up on the fact that the birds ran the other way when you yelped. I have seen that before and it generally means you should practice up on your calling or the birds have become call shy to that call. When this has happemed to me before sometimes I noticed it would help me just to swap up the call I was using. If it is the box you were using then put it down and pick up the slate, or you might try to swap up your slate surface.
I really think most of your problems come from your calling. Thats what I would focus on.