Cormorants?

With the fall season setting in, a lot of water birds have been flying through the area catching fish along the river. I go for walks sometimes along the waterfront and see lots of them. I was driving by one day and saw a whole bunch of cormorants (I think) sitting in a single tree. I happened to have my camera with me and stopped to take some pictures. As soon as I got close though, most of them got skittish and flew away. I took these pictures of the ones cool enough to stay on the tree: