Photo by Kelly Colgan Azar
Photo by Tripp Davenport
Field Sparrows are browner, with pink beaks and a plain gray face with a white eye-ring, giving them a wide-eyed, innocent expression. Their song is a beautiful whistled "bouncing ball" series of accelerating descending notes. Chipping Sparrows have a black bill, a dark line through the eye making them look a bit "squinty", and a brighter rusty cap. They are grayer overall; Field Sparrows are often a warm pinkish-brown tone (but can be gray too). The Chipping Sparrow song is really different: it's a steady trill, all on one note/pitch. Otherwise these guys are pretty similar in size, shape, and habits: they're closely related.