Coots Rails and Moorhens: Rallidae
Rails are usually colored to blend into their environments. Browns, blacks, grays, and blue-gray shades are particularly common in the group. One group of gallinules, however, tends to have brighter colors such as purples, blues, and greens. Rails often have spotted, barred, or streaked patterns. The underside of the tail is frequently differently colored from the rest of the animal. Generally, females and males are similarly colored, with a few exceptions such as the flufftails and some of the New Guinea forest rails.
Rails vary in size from 4.7 inches (12 centimeters) and 0.7 ounces (20 grams) for the black rail, the smallest member of the family, to 24.8 inches (63 centimeters) and 9.2 pounds (4.2 kilograms) for the takahe, a large, flightless rail species. In most rails, males and females are similar in size. However, males are much larger than females in a few species.
The bodies of rails are often laterally compressed, flattened on the sides, a trait which allows them to move easily through dense vegetation. Many species have long necks. The wings of most rails are short, broad, and rounded. An unusually large number of rails are flightless, unable to fly. These are generally species found on islands that have no natural predators, animals that hunt them for food. Even some rails that are able to fly sometimes escape danger by running away instead of flying. Some rails also have a sharp claw on the wing that helps individuals, particularly young rails, climb. Rails generally have short tails. Bills vary a lot among the rails, and may be long or short, straight or downwardly curved, and thick or thin. Bill shape depends primarily on diet. Rails have strong legs and feet. In some species the legs are rather long.