The bird is aptly named, since his call does indeed sound like a blacksmith's hammer hitting an anvil. He's shown here doing an after-bath wingstretch. (I took quite a few frames of him bathing, and the guide was eager to move on, but I said "Wait, he'll give us a wingstretch in just a minute." And he did.) I liked the way this shows his wing spurs. Cropped from horizontal.
D500, Sigma 150-600C @ 440mm; ISO 2000, 1/2500s @ f/6.3 manual.