Assertion: tern's tail | /r/HasProperty | gray
Facets:
value: uniformly
type: DEGREE
Source sentences:
text: It differs from the little tern mainly in that its rump and tail are gray, not white, and it has a different, more squeaking call; from the yellow-billed tern in being paler gray above and having a black tip to the bill; and from the Peruvian tern in being paler gray above and white (not pale gray) below and having a shorter black tip to the bill.
text: The upper wings and tail are uniformly gray, aside from white lesser wing coverts which form a small white shoulder when the bird is at rest.