The facial expression is priceless, with the vivid eyes, whiskers, and (seeming) smile. I'm guessing that there was a bird or a squirrel somewhere close. That transfixed look is the one that my cats have when a bird flies close to the window. I love it.
Took me awhile to learn howl. I still don't think I do it properly, but sometimes I get my desired effect. I change the saturation levels of each individual colour leaving only the colour I want to remain.