uropygial

U`ro*pyg"i*al, a. Etym: [See Uropygium.] (Anat.) Defn: Of or pertaining to the uropygium, or prominence at the base of the tail feathers, in birds. Uropygial gland, a peculiar sebaceous gland at the base of the tail feathers in most birds. It secretes an oily fluid which is spread over the feathers by preening.

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