uropygial gland
Noun
Meaning
English Wikipedia has an article on:uropygial glandWikipedia
uropygial gland (plural uropygial glands)
A secretory organ, at the base of a bird's tail, that secretes the oil used in preening.
Examples
In some birds, feather colors may be created, or altered, by secretions from the uropygial gland, also called the preen gland.
Like most other ratites, they have no uropygial gland (preen gland).
The only cutaneous gland is the single uropygial gland near the base of the tail.