lar place in a particular environment, 6

---- to secure a territory, 6, 20-72

Distribution, adjustment of, 275

Dove, Turtle, 126, 232

Dunlin, 250

Emotional behaviour, 53, 82, 114

---- manifestation, 90, 283

---- response, 26

Enemies, 282

Energy, waste of, 219

Environment, 6

---- and food, 56

---- changes of, 283

---- external, conditions in, 279, 282

Equipment, hereditary, 6

Evolution of breeding stations or territory, 15, 19

---- of the territory, 176

---- of the voice, 163

Existence, struggle for, 294

Experience, acquired, 300

Experiments, removal of nests for, 181, 185, 190, 213, 214

Exposure, its effect on nestlings, 180

External environment, conditions in, 279, 282

Falcon, 48, 71

Feeding grounds, neutral, 125 in communities, 70

Females, fighting amongst, 109-118

---- sexual impulse of, 13

Fieldfare, 124

Fighting instinct, 79, 82

Flight, emotional behaviour of Godwit during, 53

Flocks, in winter, birds collect together in, 262

Flycatcher, 244

Food, procuring of, 5

---- abundance, or scarcity of, its relation to prosperity of young,
15, 16

---- its bearing, on the movement of flocks, 262

---- rearing of young dependent on rapid and regular, 179, 195

---- supply, proximity to, necessary for rearing young, 179, 195

Fortuitous mating, 174

Fowler, Ward, on the value of communities, Rooks, 202

Fulmar, 121, 247

Functional activity, 259

---- instinct of Reeve, 173

Functioning of the disposition, 275

---- of the primary dispositions, 100

Garden Warbler, 223, 225, 230

Gaetke, H., _Birds of Heligoland_, 24

---- on the absence of song in birds on Heligoland, 124

---- on the early arrival of Guillemots on Heligoland, 64

Godwit, emotional behaviour of, during flight, 53

---- Black-tailed, 53

Grasshopper Warbler, 39, 131, 139, 153, 155, 187, 244

Greenfinch, 28, 33, 140, 235, 236

Gregarious instinct, 20, 61, 141, 265-66, 269, 276, 289, 290, 291,
296, 300

Grouse, Black, 63

Guillemot, Bridled, 64

---- Common, 63, 64, 121, 192, 195, 206, 211, 247

---- Ringed, 64

Gull, Common, 119

---- Herring, 210, 278

Habit formation, law of, 8, 62, 65, 66, 67, 205

Hawfinch, 28

Headquarters, 176, 206, 207, 274

---- restricted, 8, 9, 30, 50, 58, 64, 127

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