They are completely independent of water. Here we see internal fertilization taking place. Class Aves is for the birds, literally. These guys are the only organisms to have feathers. Many are fliers, but some remain flightless.
Birds are one of the two classes of homotherms.
Class Mammalia, is where we fall in line. Mammals have body hair and fat to maintain a steady body temperature. Mammals are also the only organisms to provide milk to their young. There's me, and my poor trout.