I believe this is a Cooper's Hawk (Accipiter cooperi; note the rounded tail and rusty brown chest). I saw him in the Ramble in Central Park in late afternoon on December 30.He flew down into a tree at the edge of Evodia Field (I think it's acalled; the large break in the canopy where the bird feeders are hung). The small birds made themselves scarce, and he sat in the tree a couple of minutes, flew briefly down to the ground, and took off southward.These aren't the best photos, obviously. I was just out for a stroll, not intending to bird, and had with me my Panny GF-1 with the 45-200 lens, which I haven't gotten the hang of for birds. It seemed to not want to focus on the bird, even using the GF1's small spot focus mode.