Assertion: pigeon's bird | /r/CapableOf | move their head
Facets:
value: constantly
type: TEMPORAL
value: in order to gauge distances
type: PURPOSE
Source sentences:
text: Birds move their head to detect the orientation of the magnetic field, and studies on the neural pathways have suggested that birds may be able to "see" the magnetic fields.
text: As a result, birds are constantly having to move their heads in order to gauge distances.