What's Up With These Feathers?

I was fascinated by this bird's chest feathers--is he just puffed up, is he sick, is it mating season, did he eat too much?--all explanations offered by well-meaning observers. "Bad burrito," says the younger guy with big muscled arms, the better to hold up his enormous lens. The older quieter guy watching the bird from the back says, "I've been here for at least 45 minutes. I'm waiting for him to fly away, but I'm almost out of battery. No kidding--I'm down to one bar!"  Photographers--gotta love 'em. Me, I just come and go with my little pocket camera.

I think it's a peregrine falcon, based on all those stripes.