Language, a necessity to thinking, 187, 188. Lark. _See_ Skylark. Lark, prairie horned (_Otocoris alpestris praticola_), spreading of, 36, 37; song and song flight of, 37, 38; killed by the locomotive, 38. Leaves, persistent and deciduous, 51. Lion, Bostock on the training of, 239-241. Loco-weed, 83. Locusts, 2. Loon (_Gavia imber_), 180, 184; under ice, 235, 236. _Lophius piscatorius_, 107. Lubbock, Sir John, on recognition among bees and ants, 200. Lynx, Canada, incredible story of, 183, 184. Maeterlinck, Maurice, on the bee, 15; on the dog, 192, 193; his _Life of the Bee_, 201. Mallard, domestic, finding its way home, 53-57. Man, progress of, 26, 27; the line that divides him from the lower orders, 80, 81; animal origin of, 229, 230; instinct in, 255; learning through practice, 256. Martin, Mrs. Annie, her story of a crow, 135, 136. Meadowlark (_Sturnella magna_), song of, 34; flight song of, 43, 232, 233. Meadowlark, Western (_Sturnella magna neglecta_), song of, 103. Mice and traps, 23, 24. Michelet, 147. Mimicry, 248-250. Mongoose, 72. Monkeys, capable of the simpler forms of reason, 127. Moose, a habit of, 142. Moral code, evolution of, 23. Morgan, C. Lloyd, 143, 149; his experiment with his dog, 164, 165. Moth, hummingbird, 249, 250. Mouse, white-footed, _or_ deer mouse, an incident, 163, 164. Muir, John, his story of his dog Stickeen, 193, 194. Mullet, 96. Mushrooms, animals eating, 83. Muskrat, 211. Mussels, ducks drowning, 180-182. _My Dogs of the Northland_, by Egerton Young, 194. "My friend and neighbor through the year," 268. Natural history romancers, influence of, 13, 14; methods of, 16, 17. Nature, an endless experimenter, 24, 139; prodigality of, 27; like a hunter, 27; bound to hit the mark, 28; the tendency to sentimentalize, 108; reaches her ends by devious paths, 110; the thinking of, 152; literary treatment of, 191-208; the interpretation of, 196-201, 203-205; wisdom of, 220. Newts, migrations of, 219. Nightingale, carrying nest, 15, 16; song of, 35; song of a caged bird, 35; a song contest, 115. _North American Review_, an article in the, 61. Nuthatch, 162. Nuts, protective colors of, 251, 252. Observing, rarity of accurate, 107, 108, 238. Olaus, his fox and crab story, 106. Oriole, Baltimore (_Icterus galbula_), a published account of a nest, 61-63; Scott's experiment with young, 68; its nest a marvel of blind skill, 110; its use of strings in nest-building, 247; an incredible story of, 248; variability of, 259, 260; song of, 259, 260; destructive in vineyards, 261. Oriole, orchard (_Icterus spurius_), 260. Osprey, 137. _See also_ Fish hawk. Ostrich, 134, 135. Ousel, water, or dipper, 73.