A friend recently sent me a photo of a Red-tailed Hawk standing over a dead gray squirrel, a fresh kill. He took a fine photo, the bird full-frame. However, he said he could not approach the bird on foot without causing it alarm and likely flight. There goes a good photo opp. Instead, he crawled toward the bird on his hands and knees, getting close enough for the photo he wanted. Years ago in Alaska, on the tundra somewhere, I wanted a photo of an American Golden Plover. When I walked toward the bird, it walked away. It wouldn't allow me close approach. So, I got down on my hands and knees and crawled into easy photo range. Perhaps the profile of a person on hands and knees is less threatening than that of a person standing.
Below, the plover.