For birds, this behaviour entails a great deal of feather maintenance. The case is no different in penguins. Although penguins do not fly, feathers must be sufficiently groomed to prevent water infiltration. In my own observations of Humboldt penguins, the early morning hours before feeding time were spent preening, both on land and in the water.
Penguins gather oil from a preening gland located on the rump, from where the tail originates.
Additionally, a penguin will enter the water and preen various regions of the body. Following this preening, the penguin will rub the flipper over the region while rotating its body as it coasts along in the water. Often one penguin may preen another penguin. These acts will be discussed in later sections. One French explorer described this event as resembling a giant turtle on the beach.