304 



INDEX 



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, 6 



— 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, neces- 



sary 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 

 Gatke, H., Birds of Heligo- 

 land, 24 



— on the absence of song in 



birds on Heligoland, 124 



— on the early arrival of 



Guillemots on Heligo- 

 land, 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 



Hedge-Sparrow, 213, 221, 244 



Hereditary equipment, 6 



Herring-Gull, 210, 278 



Hooded-Crow, 202 



Hostility and territory, re- 

 lationship between, 242 



House -Sparrow, 218. 



Imitation, vocal, powers of, 



156, 157, 161 

 Impulse, internal, 279 



— to brood, 191 

 Inherited disposition, 5 

 Instinct, fighting, 79-82 



— gregarious, 20, 61, 141, 265, 



266, '269, 276, 289,290, 291, 

 296, 300 



— migratory, 37 



— of song related to establish- 



ment of territory, 125 



— sexual, reawakening of, 4, 18 

 Instinctive response, 180 

 Instincts susceptible to stimula- 

 tion, 259 



Internal impulse, 279 



