My son and I were at a park walking next to some water. I went to peek in the woods to see if I could see any deer and as I turned around there is this bird shaking its wings at me. It made me jump back a little because the way it was shaking (think about the dino that shakes its neck in Jurassic Park). It was on the ground and guessing it was sitting on a nest even though I saw no eggs.. It was about the size of a chicken and had a long slender sort of curved beak. Any ideas?