23 September 2015
There’s a hollow knocking sound you often hear in the woods but you rarely see who’s making it. Tock Tock Tock Tock, the sound travels and is echoed by additional singers.
The knocking is a chipmunk warning call that means “Danger From The Air!” One chipmunk has seen an aerial predator and has frozen in position to warn everyone else that they’d better watch out. The other chipmunks freeze too and echo the call until it’s impossible to tell where the warning began.
The video below shows the sound as we usually encounter it — a disembodied knocking. In this case it’s louder than thunder.
When you hear the Tock sound, look for a raptor. One of the chipmunks knows where it is.