The Gymnast, The Dreamer and The Commander

I was leaving Bear River refuge when I noticed a Yellow-headed black bird.
It was getting dark and my first thought was that light was so low
that I wold not get sharp pictures.
Then in a few seconds another Yellow-headed black bird appeared.
And soon there was a colony of them 
sitting on the tall plants and loudly chatting.  

First, I took pictures of the Gymnast (picture above).
It's a male. He has a brilliant yellow head and black body.

Then I took pictures of the Dreamer, he is also a male.

The Dreamer

 


And later we worked together on a portrait of the Commander.
Why is he the Commander?   
When he left his plant with rich call/croak 
every single Yellow-headed black bird was gone.