This is one peculiar bird! One or two birds will vocalise in a chit-chat manner but when they are several more, the synchronized sound created is otherwordly!
First I thought I heard some distant machinery – perhaps from a plane, but around the bend of the creek a flock of perhaps 20 Anis were chanting in a way I’ve never heard from any bird. It was like a tribal event – all synchronized! A truly remarkable sound and harmonics!
Fortunately the recording below gives a sample, but I experienced much stronger and higher sound.