Feathers are essential for birds. These outer elements protect them from the elements, camouflage them from their predators or make them attractive during mating. The feathers are composed of shaft and vane. The shaft has a part called rachis and one called calamus, this last is the hollow part that is inserted into the skin. The vane is made up of beards and barbels. Due to their proximity to the bird's body, feathers are classified as: down feathers, contour feathers and flight feathers: rowing feathers on the wings and rudder feathers, on the tail. Due to its importance, feather´s grooming is a survival task. This infographic from the Ábaco collection is part of The Art of Flying series, which also includes those originally titled: Why Do Birds Fly, Adapted Arms,  The Tail as a Rudder, So is Gliding Flight and So is Flapping Flight.