Preening Is Hard Work!
Preening Is Hard Work!. © Debi Dalio/Getty Images

Definition: Preening is the process by which birds groom and care for their feathers. When a bird is preening, she uses her beak to pick through her feathers -- removing any debris, arranging feathers that are out of place, and distributing a special oil that is secreted from a gland at the base of the tail. This oil helps a bird's feathers stay healthy and shiny. It is their way of maintaining their protective coat that ensures that they can fly, stay dry and stay warm in cold weather.


Preening is a natural and instinctive activity birds engage in to groom and clean their feathers. Preening is a bird's normal way of straightening out their feathers to keep them fit for flight as well as to keep their feathers waterproof and well cared for.

There are many different types of feathers that all serve different purposes, but they all need attention and they all need to be looked after. 

Feathers are made up of the protein beta-keratin. Feathers have microscopic hooks on the barbules that interlock and hook up with each other to form a barrier that effectively keeps out wind and rain. What preening does is kind of like buttoning up your overcoat before you go outside. This "buttoning up" of the feathers has many uses but it also is what allows the bird to control the feathers during flight. 

The feathers on a bird are generally arranged in an overlapping pattern very much like scales on a reptile.

This overlapping pattern is another protective adaptation that keeps the elements away from the bird's skin.This overlapping pattern which occurs naturally by the angle of the feathers growing out of the bird's skin needs to be meticulously maintained in order to provide the protection the bird needs.

So straightening these feathers out, hooking up the barbules and dressing the feathers to keep them waterproof is what preening accomplishes. 

Feathers serve several purposes in the life of a bird. They of course allow the bird to fly, but they also allow the bird to show off to other birds during mating season as well as keeping a female bird hidden and camouflaged while she is sitting on a nest or caring for her babies. 

Not all feathers are used to attract a mate. Some in fact are used as forms of aggression. You will find certain species of birds that will raise a crest on their heads if they are agitated or feel threatened. 

This preening is crucial to birds who spend a lot of time in the water. Waterfowl such as ducks, loons and geese need to maintain their feathers meticulously so that they may maintain a state of being waterproofed. If they do not keep up this meticulous grooming, they can become waterlogged and this is indeed a threat to their survival. 

Many birds have what is called a preen gland located at the base of their tail where it meets their back.

You might see your bird reach back to her tail and rub her beak on it. What she is dong is stimulating that gland to produce oil. This secretion of oil is then rubbed all over her feathers when she preens them with her beak. This oil "dresses" those feathers in a way.  It provides the waterproofing of course, but there is another purpose. 

Many birds, particular parrots need Vitamin D. In order to absorb this critical component to good health, they need sunlight. But simply being in the sun doesn't provide them with this vitamin. They have to ingest it. What happens when they preen using the oil from the  preen gland, also called the uropygial gland is quite interesting. The oil from the gland that is on the feathers absorbs the Vitamin D. When the bird begins to preen again, they ingest the oil that is on their plumage that has this vitamin in it. 

So when you see your bird diligently and scrupulously fussing with her fancy feathers as well as rearranging them and stripping her beak at the base of her tail, you know that she is simply making sure that her feathers stay in good shape. 

Edited by: Patricia Sund