" Hawks have a flying weight, just as boxers have a fighting weight. A hawk that’s too fat, or high, has little interest in flying, and won’t return to the falconer’s call. Hawks too low are awful things: spare, unhappy, lacking the energy to fly with fire and style. Taking the hawk back onto my fist I feel for her breastbone with the bare fingers of my other hand. She is plump, her skin hot under her feathers, and through my fingertips I feel the beating of her nervous heart. I shiver. Draw my hand back. Superstition. I can’t bear to feel that flickering sign of life, can’t help but suspect that my attention might somehow make it stop. "

― Helen Macdonald , H is for Hawk