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, 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, 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 



ttlack-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, 



266,1269,276,289,290,291, 

 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 



