散る: blossoms falling in the wind and birds scattering at a signal
Read 散る through falling cherry blossoms and scattering birds. Compare their subjects, triggers and the past 散った with the nonpast 散る.
Blossoms, wind and 散った
散る (ちる) can mean to fall or to scatter. 「風が吹くと桜の花が一斉に散った。」 means “When the wind blew, all the cherry blossoms fell at once.” Cherry blossoms are the subject, and the wind is the trigger for their falling.
散った reports the falling as a past event. Wind is given as the trigger, but the sentence does not describe the flowers being uprooted. Falling blossoms and plants being pulled out are different descriptions.
Gathered birds, a signal and 散る
「合図とともに集まっていた鳥が四方へ散る。」 means “At the signal, the gathered birds scatter in every direction.” The birds scatter at a signal, and 散る is a nonpast description rather than the past form used for the blossoms.
集まっていた describes the birds' previously gathered state, while 四方へ gives their scattering direction. The stated signal supplies no additional threat or predation event.
The subject determines what falls or scatters
桜の花 and 鳥 distinguish the two readings in these sentences. Blossoms fall, whereas the birds disperse as a group. The birds' scattering does not describe them withering or dying.
The triggers are also different: 風が吹くと and 合図とともに. Keeping the past 散った and nonpast 散る preserves the separate descriptions instead of joining them into one completed past event.
How do the meaning and trigger of 散る differ in 桜の花が散った and 鳥が四方へ散る?
Show the answer and why
The blossoms fell when the wind blew; the gathered birds scatter at a signal. The subjects and triggers differ, as do the past 散った and nonpast 散る. The birds' dispersal is not withering or death.