When many people see birds preening and cleaning their feathers, they attribute it to vanity on the part of the bird.
But, in reality, what they are doing is maintaining their wings, the instruments that they depend on for safe flight.
If a bird's wings are not in perfect condition, the bird either won't be able to fly or won't be able to control its flight.
That is why after a long flight and even throughout the day, you will see them cleaning and straightening their feathers.
Most birds, if they get a chance, will take a bath at least once a day.
They do this to get rid of the dust that has accumulated in their feathers throughout their flights during the day.
After the bath, they will shake the water out and begin the process of combing and smoothing their feathers.
If you watch them carefully, you will see them meticulously pass each feather through their beak, multiple times if necessary, to ensure that the feather and its aerodynamic capabilities are just right.
In dry or desert areas, birds will not always be able to find water in which to bath, but they still need to clean their feathers.
What many birds will do is to take dust baths.
They will roll around in a dusty patch until it covers their feathers.
They will then stand up and shake the dust out, similar as to how they shake water from their wings when they have a water bath.
They will then clean their feathers with their beaks, as usual.
Baths are important for another reason also.
During the course of the day and nights, many parasites are attracted to birds.
Bugs, mites, fleas, and so on will try to hitch a ride on birds and suck from their blood.
Daily baths help to keep the parasites to a minimum.
Some birds, especially those that spend a lot of time in or around water, have skin glands that produce oil.
After bathing, these birds will squeeze the glands to prompt them to excrete oil.
They will then spread the oil over their wings.
This helps to waterproof them and keep them from getting waterlogged.
If you are a bird lover and have bird houses and feeders in your yard, it can be good to go the extra step and provide a bird bath as well.
Once the birds in your neighborhood discover it, you will be surprised at how popular it becomes as they periodically stop by to take their daily bath.