preening Grooming behaviour that is performed by birds for the maintenance of feathers. Preening cleans feathers, but also oils them with a substance secreted by a preen gland near the tail; the bird applies this substance with the tip of its bill. The oil renders the feathers supple and water-resistant, and ingested oil supplies the bird with some vitamin D.

preening Grooming behaviour that is performed by birds for the maintenance of feathers. Preening cleans feathers, but also oils them with a substance secreted by a preen gland near the tail: the bird applies this substance with the tip of its bill. The oil renders the feathers supple and water-resistant, and ingested oil supplies the bird with some vitamin D.