Clark Park at about 4 p.m. yesterday looked and sounded as usual. Kids playing after school; their parents nearby chatting. People walking their dogs or reading the paper. Then things changed for a few minutes when a large red-tailed hawk swooped down, grabbed a squirrel and perched about 20 feet off the ground near the older kids’ playground. The hawk sat on a branch with the squirrel dangling from its talons as people gathered underneath the tree to get a better look – the parents of younger children looking a little nervous. The hawk, one of many that call Philadelphia home, lingered for 20 minutes or so before taking his dinner to a more secluded location.