Y6 FIELD KEY TO COMMON BIRDS. It should be borne in mind tbat living birds do not look as long as they really are. The measurement of " length " is taken with the bird's neck and tail out- stretched in a straight line. In life the tail may be raised or drooped, while the neck is drawn in or curved, making the bird look shorter than measurement shows it to be. Remember that the Robin measures ten inches, the House Sparrow six and one-fourtli inches, and the Ruby-throated Humming-bird three and three-fourths inches in length, and you will have a basis for comparison. FIRST GROUP. BIRDS THAT FEED ON THE WING FOR LONG INTERVALS OF TIME WITHOUT PERCHING. {Sivallows, Swift, Nighthaivh, Whip-poor-will.) I, Size large, length over 9-00 inches ; the spread wings over IS'OO inches in extent ; generally seen only late in the afternoon or at dusk. 1. A bird of the air, flying high, often over housetops in cities; a conspicu- ous white spot in each wing ; note, a loud, nasal jPec/^i ; sometimes dives earthward with a boom ingr sound; May to Oct. . Nighthawk, page 118. 2. Haunts, near the ground, not often observed while feeding; call, given from a rock, stump, or similar perch, whip-poor-will, vigorously repeated ; Apl. 25 to Oct AVhip-poor-will, page 119. II. Size smaller, length under 9-00 inches ; the spread wings less than 15"00 inches in extent ; may be seen at any time of the day. 1. Plumage entirely black. a. Length 5-50 inches; plumage sooty black ; usually nests in chimneys; Apl. 25 to Oct Chimney Swift, page 119. b. Length 8-00 inches ; fflossy, bluish black ; nests in gourds or houses erected for its use ; Apl. 25 to Sept. . . . Purple Martin, page 161. 2. Plumage not entirely black ; Apl. to Oct. . Swallows, pages 159, 160. SECOND GROUP. CLIMBING AND CREEPING BIRDS. {Nuthatches, Creepers, Woodpeckers.) I. Birds ivithout stiffly pointed tail-feathers, that climb either up or down. 1. Length 6-00 inches; back gray, cap black, clieeks and under parts white ; note, a nasal yank, yank ; a permanent resident. White-bkeasted Nuthatch, page ISO.
