Assertion: petrel's bill | /r/CapableOf | patter the surface
Facets:
value: often
type: TEMPORAL
value: to steady themselves
type: PURPOSE
value: with their feet
type: MANNER
Source sentences:
text: They prey mostly on zooplankton and small fish, which they capture by hovering above the ocean and dipping down to grasp with the bill, often pattering the surface with their feet to steady themselves.