What function does the preen gland serve in birds?

The preen gland, also known as the uropygial gland, is located near the base of the tail in many species of birds. Its primary function is to produce a natural oil that birds use to maintain their feathers. This oil helps to waterproof the feathers, keeping them strong and flexible while protecting the bird from moisture and ensuring efficient insulation against temperature fluctuations.

By preening, birds smear this oil onto their feathers, which is crucial for maintaining their condition and performance in flight as well as for overall hygiene. The oil also contains substances that can have antifungal and antibacterial properties, helping to protect the bird from infections.

While other functions such as supporting skeletal structure, aiding in digestion, or regulating body temperature are vital for birds, they are not functions of the preen gland. These aspects are managed by different anatomical structures and systems within the bird’s body. Thus, the role of the preen gland is specifically focused on feather maintenance through the production of oil.