An angry Pelican

This Pelican just wanted some space, and another was getting a little too close. It was actually the first time I've ever heard a Pelican make a vocal sound. It was an obvious warning blast, and the other Pelican got it loud and clear.
Not the sound I expected - not that I had any expectations of what a pelican would actually sound like - like a clicking or knocking sound, over the top of a low groan. Like a didgeridoo in higher pitch!

Had to add this perfect little limerick, thanks to JanB

A wonderful bird is the Pelican
His bill can hold more than his belly can
He can hold in his beak,
Enough food for a week
I just don't know how the hell he can!