In plain sight in this photo from August 1998 on this website. With some other interesting swirls.
http://www.themodernantiquarian.com/img_fullsize/573.jpg
It is always good to look at a site with fresh eyes. Or you will only see what you think you are going to see - and nothing else. ie. if you think you are going to a site to see cups, rings and swirls then that is all you will look for and see.
When you zoom in to the third image in your original post, there looks like clear "peck" (sic) marks at the rock under the bird's chin area. Have a gander.