Squirrel Hunting 2010

Sitting in the woods at any time will give an adventure for someone to appreciate some time with mother nature. I went out for squirrels on opening day and brought home 4 nice bushytails. That first week was a good week for them, but now it seems they hole up and dont come out at all. I have sat mostly in the afternoon/evening and can hear them moving on occasion, but its mostly chipmunks. It's almost like they see someone walk in with a gun and they all stay in their nests. I hunt a lot of public land, many different spots, and a few spots of private land. I have the same issue at all the places that I go. Is it just too early for them to be out and about, or am I doing something wrong? I start out with picking a spot to hunt, listen for any activity, and when I pick up on things I try to stalk over to the area. But if things are really slow, I try to stay quiet and not move too much.