Assertion: black swan's feather | /r/HasProperty | stained orange-brown
Facets:
value: in the water
type: LOCATION
value: by iron
type: OTHER
value: often
type: TEMPORAL
value: by tannins
type: OTHER
Source sentences:
text: All mute swans are white at maturity, though the feathers (particularly on the head and neck) are often stained orange-brown by iron and tannins in the water.
text: The white feathers present on the heads and necks of adult mute swans are often stained orange-brown by iron and tannins in the water.