Adjective
Of or pertaining to the uropygium, or prominence at the base of the tail feathers, in birds.
Source: Webster's dictionaryIn some birds, feather colors may be created, or altered, by secretions from the uropygial gland, also called the preen gland. Source: Internet
Like most other ratites, they have no uropygial gland (preen gland). Source: Internet
The only cutaneous gland is the single uropygial gland near the base of the tail. Source: Internet