Assertion: duck | /r/HasAspect | special gland
Facets:
value: like many birds
type: OTHER
Source sentences:
text: Like many birds, ducks have a special gland called a preen gland near their tails that produces oil.
text: Ducks have a Special Gland that produces Oil near the Duck's Tail which spreads and covers the outer coat of the Duck's Feathers, making it Water-proof.