I photographed all four of these falcons on Aqua Vitae Rd. in Hadley, Massachusetts, in January - March 2013. This is a composite of four photographs, with each bird sized proportionately to the others. The Gyrfalcon is the largest and the American Kestrel is the smallest. A Merlin is only slightly larger than the Kestrel, and the Peregrine Falcon is only slightly smaller than the Gyrfalcon.