chorusing

Frogs were chorusing in the near swamp, and Bobby wanted one.

A ghoul might seem to have set it going, and laughing hyenas to be chorusing it.

Flocks of them followed at a distance, a train of worshipers, chorusing the glory of the new-born wonder.

As we went along, they were audible at every station, chorusing wildly out of tune, and feigning the highest hilarity.