Francis Heatherley, The Peregrine Falcon at the Eyrie… (1913)
“ The Falcon flew off as we approached the eyrie, and immediately started calling the alarm as she circled overhead. Her harsh cry seemed to me to be more like "aitch, aitch, aitch" than the "kek, kek, kek" of the books. I never could tell them apart when flying, but when together it is plain that the Tiercel is smaller and his alarm note different and rather higher in pitch. Their flight consisted of a series of rather laboured beats followed by glides on outspread wings. The young formed a round heap like a pancake raised in the middle. Before we disturbed them there was only one head visible. ”
