Bird's Eggs

This is what happened to me yesterday morning: I'm pulling in the parking lot at work and there is a squirrel running up the drive in front of me with a bird on its back. Of course I'm thinking of all days not to have my camera with me! I pull in my parking place and watch them. The squirrel is running and the bird is on his back flogging him. The squirrel runs up a fence and then jumps in a tree and the bird is right behind him. The squirrel runs way up high in the tree and of course the bird is right there, but then the bird flies away. I'm thinking now that's the weirdest thing I have ever seen. A few minutes later one of my co-workers comes in my office holding a blue egg. She said look what I found in the parking lot. Wonder were it came from because there are no trees in the parking lot. I said oh my gosh....that squirrel must have had that egg and that's why the bird was so upset. So we went outside and looked around where the squirrel had run from and we found a nest in a bush. I don't know if the egg fell out or the squirrel climbed in after it. At lunch I went home and got my camera and came back and took this picture. I love the color of these speckled eggs. I don't know what kind of bird it is. I think it was a grey color because it flew out when we approached the bush. We laid the egg in the nest hoping she would take care of it. We don't even know if it is hers or not, but I'm gonna keep a check on it. Anyway, I thought it was quite interesting.