Assertion: antarctic petrel | /r/CapableOf | comprise thousands of birds
Facets:
value: on ice floes
type: LOCATION
value: sometimes
type: TEMPORAL
Source sentences:
text: Antarctic petrels are gregarious at sea and roost on icebergs in flocks comprising thousands of birds.
text: They are often seen in flocks, sometimes comprising thousands of birds, on ice floes.