The act of a bird using its beak to clean, arrange, and condition feathers by distributing preen oil from the uropygial gland at the base of the tail. Social preening between bonded birds is also common.
Healthy preening indicates good feather condition. Reduced preening signals illness, stress, or pain and should prompt a vet visit.
Offer bathing opportunities before preening sessions — wet feathers are easier to arrange and preening after bathing distributes oils evenly.