Wood ducks

I noticed something yesterday which caught me by surprise.  First, I saw these wood ducks up in some eucalyptus trees.  (I have never seen ducks in a tree before, so this in itself was a little surprise.)  Second was the sound they were making.  We have heard this call plenty of times before but had never actually seen the bird while it was making it.  Since it sounds like a kookaburra wind-up, I'd always assumed before that that's what it was.  Now I know!

Below is also a brief video so you can listen to the sound.  (There's also a magpie lark call followed by some magpies yodeling, but the wood duck is the quiet chuckling that continues throughout the video.)