capable of part of capable of part of produced by produced by grooming behavior personal grooming secretion of exocrine gland uropygial gland preen oil preen gland secretion UBERON:0007803 uropygial gland secretion The uropygial gland is involved in maintaining feather condition and secretions spread by preening. It serves a waterproofing function. The secretions contain a pro-vitamin D, converted by UV light to active vitamin D. The secretions are also believed to suppress the growth of micro-organisms, serving an anti-bacterial function. [http://en.wikivet.net]