Scout, a golden retriever, and Tia, an English cocker spaniel, are both bird dogs. They hunt duck, quail, and pheasant. I watched a demonstration by Rose, Scout's sister, last weekend, and she is impressive! She heels, sits, waits, and then fetches -- all on command. She responds to voice, hand, and whistle signals -- all with alacrity. She finds the birds (dummies, in this case), she brings them back, she releases them, and then she begs for more. It's amazing to watch a dog who is so enthusiatically committed to her work!
I should add that this working relationship is much like the one I have with my dog, Kinsey, only in reverse. Kinsey gives the commands -- voice, paw, eyebrow -- and I hop to with alacrity. I'm sure my eagerness to work on Kinsey's behalf gives her great pleasure, too.