The Double-Crested Cormorant is abundant here in Southern California. We see them on the rocks and swimming all the time. They are expert fishers. They are diving bird. They dive straight from their floating position. They can swim underwater using their powerful and large webbed feet for quite a distance before they pop back up to the surface for air. If they have caught a fish you will see them toss the fish in the air and catch it so it goes down their throat the right way. Most marine birds have waterproof but the Cormorant is not. So you will see them on the rocks with their wings spread out to dry. They are large birds that can reach up to three feet long.
This guy followed me all around the tidepools one day like a dog!