[chubot]

Are the birds imitating sounds they heard in the forest?

Mimicry is a powerful thing

[dylan604]

I went deeper down the rabbit hole, and it is their mating call / territorial signal. The drumming sound is actually created from a vacuum effect caused by the particular movement of their wings. https://www.youtube.com/watch?v=vERkh23mp64

[tejtm]

It's a mating call that predates combustion engines most likely by millennia(s)

[dylan604]

I wonder how long Poly has wanted a cracker

[tejtm]

Two billion years give or take