Birds, mistakes of, 4-6; their nest-building, 4, 5, 70, 71; fighting their reflections, 5, 6; taking advantage of man's protection for their nests, 6, 7; probably make no improvement in nest-building or singing, 70, 71; learn cunning by experience, 71; instincts connected with parasitism, 79, 80; communication in flocks of, 96-98; courtship of, 103, 104; activities of the two sexes among, 111-114; song contests among, 114, 115; and glass, 127; incubating-habits of, 135; shading mate and young from sun, 137, 138; their knowledge of the value of protective coloration, 138-140; migration of, 186; their affection for their young, 215; and shell-fish, 216; have no power of initiative, 232, 233; their handling of strings, 246-248; instinct in, 256-261; variability in, 258-261. Bird's-nests, an epitome of wild nature, 109; haphazard design in, 109, 110. Bird-songs, the power to hear, 29; not music, 29; elusiveness of, 30; a part of nature, 30; our pleasure in them from association, 31-34; songs of caged birds, 32, 35; the wing-song, 39-44; individual variation in musical ability, 44-46; acquired by imitation, 67, 68. Bittern, least (_Ardetta exilis_), eating her eggs, 111. Blackbird, crow, or grackle (_Quiscalus quiscula_ subsp.), catching a fish, 176; enmity with robins, 263, 264. Blackbird, English, song of, 45, 227. Blackbird, red-winged. _See_ Red-shouldered starling. Black-knot, 27. Bluebird (_Sialia sialis_), hearing the, 29. Bobolink (_Dolichonyx oryzivorus_), its song in the home meadows, 36; variation in song, 69; with defective song, 116. Body, the, intelligence of, 128. Bolles, Frank, 18. Bostock, Frank C., his _The Training of Wild Animals_, 239-242. Brewster, William, 22. Buds, formation of, 50, 51. Bumblebee, hibernation of, 49. Burmeister, quoted on bees, 200. Calf, a wild, 214; a yearling and its muzzle, 237. Canary-bird, 159; an incredible story of a, 177, 178. Carlisle, Bishop of, 148. Cats, 66, 67, 73; fear of dogs, 75; talking with the ears, 94, 95; playing with mice, 100; watching a mouse-hole, 186, 187; human qualities of, 225, 226. Cat tribe, their method of hunting, 183, 184. Cedar-bird (_Ampelis cedrorum_), notes of, 46; nest-building of, 112; and strings, 247, 248; no song impulse in, 257. Chapman, Frank M., his story of a least bittern, 111. Chewink, or towhee (_Pipilo erythrophthalmus_), the "Hermit's" story, 93. Chickadee (_Parus atricapillus_), flight of a young, 70; tameness of, 205. Chipmunk, 159. Coon. _See_ Raccoon. Cow, the, ignorance of, 123, 124, 187, 221. Cowbird (_Molothrus ater_), 79, 80, 156, 157; an incredible statement regarding, 178, 179, 220. Coyote, or prairie wolf, 82, 86, 189. Crab, hermit, 155.