This is just a guess.

This is another hard yet interesting one. It's tough with the lines that precede it because I'm not sure what, exactly, they're trying to get at.

Again, I think it is important to get the message across in a way that preserves the meaning and the history behind the song. That is why I think it was so important to include Buenos Aires in the last question.

If you just said, "the rumor of the white handkerchief" the entire political context would be lost. Of course, my translation doesn't refer to las madres de la Plaza de Mayo, either.

Just something to get the ball rolling!

a white-scarved whirr/hum/drone

or

a hum/vibration/whirr/drone of white scarves

Several options to flesh out the idea.

whir

whir [wur, hwur]
whirr [wur, hwur]
transitive and intransitive verb (past whirred, past participle whirred, present participle whir·ring, 3rd person present singular whirs) (past whirred, past participle whirred, present participle whir·ring, 3rd person present singular whirrs)
make a whirling or vibrating sound: to make a continuous soft buzzing or humming sound, usually by vibrating or turning very quickly, or to cause something to make such a sound


noun (plural whirs) (plural whirrs)
whirling or vibrating sound: a continuous soft buzzing or humming sound like that of something vibrating or turning very quickly


[14th century. Origin uncertain: probably from a Scandinavian source.]
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Creo que esto cabe mejor dentro de la medida de una canción o un poema.