Double-crested Cormorants may look clumsy, even comical out of the water, but in the water they are swift and agile swimmers. They are a big bird with a solid build and a 4 foot wingspan. Unlike most birds, they have solid, dense, heavy bones and feathers that are not water proof. This makes them set very low in the water, with nearly their entire body underwater. These are the characteristics however, that make them such good swimmers. They can dive up to 30 feet deep, swim 38 miles per hour, and stay under for 30 seconds. They will typically fish for an hour, then they must sit on a perch to dry out their feathers.