Adult, American Sparrow, Animal, Bay Area, Binocular, Biologist, Bird, California, Caucasian Appearance, Color Photograph, Cultural, David Luther, Day, Emberizidae, Head and Shoulders, Horizontal, Least Concern, Lobos Dunes, Looking, Male, Man, Mid Adult, North America, Nuttall's White-crowned Sparrow, One Person, Outdoors, Presidio, Research, Researcher, Researching, San Francisco, San Francisco Bay Area, Science, Scientist, Side View, Songbird, Sparrow, United States, United States of America, USA, Watching, White-crowned Sparrow, Wildlife, Zonotrichia leucophrys, Zonotrichia leucophrys nuttalli, Zonotrichia sp