Assertion: hummingbird | /r/CapableOf | migrate in response
Facets:
value: to hormonal changes
type: CAUSE
value: to day length
type: OTHER
value: to a decline in day length
type: CAUSE
Source sentences:
text: Hummingbirds migrate in response to a decline in day length, not food availability.
text: But, hummingbirds migrate in response to day length, not food supply, so leaving a feeder up will not hinder the hummers migrating.
text: However, hummingbirds migrate in response to hormonal changes (triggered by decreasing daylight) - so whether or not a feeder is up won't impact their natural urge to migrate.