herrings, 115; nesting habits difficult to observe, 115, 116; probably eats heads of herrings disgorged for young, 117, 118; has no reason to vary diet during breeding-season, as asserted, 118; suggested origin of its specialised method of feeding, 118, 119; attacks those approaching its nest, 121; makes swoop in silence, but utters cry whilst circling between each, 121; blow with feet ineffective, 122; attacks almost indefinitely, 122; mode of attack, 123, 124. Attack made by both sexes, 124; an exception noted, 124, 125; theory in regard to this, 125. Feared less by gulls than Arctic skua, 128; mobbed by gulls, 128
Skylarks, aerial combats of, 35, 36; impressive hops of male in courtship, 49; song of, how differing from the nightingale's, 312; effect of if heard at night.
Snipe, a familiar example of instrumental music during flight, 52; modification of tail-feathers by sexual selection, 53; wings apparent but not real cause of bleating, 53, 54, 55; different ways of descending to earth, 53, 55, 56; different modes of flight, 54; see-saw or "chack-wood" note, 54, 56; swishing of wings, 56; extraordinary notes of, 57. Tail feathers less modified in female, and producing a different bleat, 57; but difference not great, 57, 58. Individual differences in bleat, 57, 58; flying in circles, 58; bleat best in morning and evening, 58; flight difficult to follow, 58; private allotment in fields of air, 58; bleating of males against each other, 59; bleating of male and female to each other, 59; bleating of one answered vocally by the other on ground, 59. Extraordinary movements when alarmed during incubation, 61; theory with regard to these, 63, 64
Sparrows, seize burrows of sand-martins, 325; creditable motives of, in so doing, 325, 326
Sparrows, Tree, at straw-stack in winter, 199; seize burrows of sand-martins, 325
Species, knowledge lost by destruction of any, 333
Specific life, any, of more value than most individual ones, 334
Spiders, if they had their Phidiases, 52
Spur-winged Lapwing, curious performances of, 81, 82; suggested origin of, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95
Starlings, acting as fly-catchers, 8, 48; and as wood-peckers, 48. Manner of feeding, 9; at straw-stack in winter, 199, 204, 205; fighting with hen blackbird, 204; fighting with each other, 204, 205. Their simultaneous flights, 210, 214, 215; difficulty of explaining these and suggestions as to, 214, 215. How associated with rooks, 261
Stock-doves, their aerial combats, 38, 39; arising sometimes out of the ground-tourney, 41, 42. Their ground-tourneys, 39, 40, 41; bowing of fighting birds to each other, 39, 40, 41; fighting of male and female, 42, 43; courting bow of male to female, 43, 44, 45; bowing of female to male, 43, 44; bow silent or accompanying note subdued, 45; court on trees or on ground, 45; their nuptial flights in early morning, 46, 47; make nest in rabbit-burrows, 47
Structure, slight changes of, not easy to see, 229
Thought-transference, as possible explanation of some movements of birds and other animals, 219, 220, 221, 222, 223, 286,
