Observations on Food, Nesting, and Winter Populations of Large North American Falcons

During the course of a biosystematic study of the Peregrine Falcon (Falco peregrinus) by White over the past few years, observations have been made on several species of North American falcons. While all three large species (Prairie Falcon, Falco mexicanus; Gyrfalcon, Falco rusticolus; and Peregrine) have been subjected to detailed study by various writers, a few additional notes on their biology are reported herein. We would like to acknowledge the help in the field of William Tilton, Anchorage, Alaska, and the late Gary D. Lloyd of the University of Utah for stimulating discussions of the data presented. Marvin R. Meyer, of Salt Lake City, provided some data on Prairie Falcons.