Assertion: great black backed gull | /r/HasProperty | l. fuscus
Facets:
Source sentences:
text: In adults, the lower black-backed gull (L. fuscus) is apparently smaller, usually about half the weight of a great black-back.
text: The adult lesser black-backed gull (L. fuscus) is distinctly smaller, typically weighing about half as much as a great black-back.