Thanks for all the comments guys! Teh, as far as can tell those hole have been there for a while because they are definitely not fresh.
We scored a couple more points over the weekend. LOTS of snail, muscle, flint and bone coming from the top layer. We have already found quite a few small pieces of pottery. I decided to go deeper and found another layer about 8 inches below the birdies. Not sure on the age yet because i haven't found any points down there.