Definition of "susurration"

Most of the Hummers are honey-lovers, and they extract the sweetest juices of the flowers. The "soft susurrations" of their wings, as they poise above the flowers, inserting their long beaks into tubes of nectar, announce their presence.

1898, Birds and All Nature, volume 4

The rain was now falling more steadily, with a low, monotonous susurration, interrupted at long intervals by the sudden slashing of the boughs of the trees as the wind rose and failed.

1907, Ambrose Bierce, Beyond the Wall

"If only that last part is a translation…." said Dalton hopefully. Then the alien susurration ceased coming from the reproducer and he closed his mouth abruptly and leaned forward.

1954, Robert Abernathy, The Record of Currupira

Halleck nodded, heard the faint susurration and felt the air shift as a lockport swung open beside him.

1965, Frank Herbert, Dune