Uropygial gland
From Wikipedia, the free encyclopedia
The uropygial gland, or, more informally, the preen gland is a gland found in the large majority of birds that secretes an oil (preen oil) that birds use for preening.
The gland is found near the base of the tail and is shaped into two symmetric parts. The oil of each part of the gland is secreted through the surface of the skin through a pimple. A bird will typically transfer this oil to its feathers by rubbing its head against the oil and then around the rest of the body.
Not all birds have a uropygial gland. Exceptions include the emu, ostrich, and bustard. These species typically find other means to stay clean and dry, such as taking a dust bath.
