CHAPTER VIII. A FIELD KEY TO OUR COMMON LAND BIEDS. AVhen you have seen a bird with sufficient definite- ness to describe its color, form, and actions, reference to the following key will often prove a short cut to its identity. This key is based only on adult males, who, because of their song, often brighter colors, and greater activity, are far more frequently observed than the females. But, knowing the male, you will rarely, during the nesting season, be at loss to recognize his mate. In order to simplify the key, the water birds, Hawks, and Owls are omitted, in the belief that they will be more readily identified by reference to the plates. The use of the key may be illustrated by the follow- ing example : Let us imagine that you see a Chipping Sparrow (Plate XLY) feeding about your doorstep. You note his size, chestnut cap bordered by white, black bill, brownish, streaked back, and grayish white, un- marked under parts. Turning now -to the key, you will see that by exclusion the bird belongs in " Section V " of the " Third Group," and that it should be placed in subsection " 1 " of this section, which includes birds hav- ing the " under parts white or whitish, all one color, with- out streaks or spots." You have now two subdivisions to choose from — "A. Back without streaks or spots," and " B. Back brownish, streaked." Your bird falls under " B," where again you have two subdivisions, " a. Crown rufous or chestnut, without streaks," and " h. Crown not rufous or chestnut." Your bird should be referred to " a," where you will at once find it described under " a^ " as the Chipping Sparrow. 75
