X A HISTORY OF BIRDS 



CHAPTER V 



PAGE 



Seasonal Life. Relations to Moisture, Temperature, etc., and to 



Periodic Changes in the Cosmosphere °° 



The bleaching effect of light. Desert forms. The effects of a saturated 

 atmosphere. Arctic conditions. Size and latitude. Storms and 

 drought. 



CHAPTER VI 

 Migration - * ^9 



Kinds of migration. Routes. The height at which birds fly. Speed. 

 Lighthouses and their influence. Erratic migration. Causes of 

 migration. Meaning of migration. 



CHAPTER VH 



Relations to the Animate Environment io6 



Relation to plants. Birds and pollination. Birds and spread of seeds. 

 Birds in relation to other animals. The perils of nestling birds. 

 Birds and " civilisation ". 



CHAPTER Vni 

 Peculiar Interrelations 124 



Ostriches and Zebras. Rheas and Guanacos. Oxpecker and big Game. 

 Egrets and Elephants. Bee-eaters and Bustards. Penguins, Alba- 

 trosses and Petrels. Osprey and small birds. Chaffinch and 

 Missel-thrush. Burrowing Owl and Prairie-dogs. Petrels and 

 "Tuatera Lizard". Puffins and Rabbits. Skuas and Gulls. 

 Frigate-birds and Gannets. Cuckoos and their dupes. The causes 

 of parasitism. 



CHAPTER IX 

 Phases of Social Life - 135 



Gregarious birds. Curious sleeping habits. Pelicans fishing. Wood- 

 peckers and food stores. Significance of gregarious habits. 



CHAPTER X 

 The Relations of the Sexes .... . . j ., 



The division of labour in nest-building. Manifestations of sexual activity. 

 Forms of this activity. Plumage displays. "Sdcaleli." Wind-bags 

 and display. Tournaments. Weapons and their uses. Dancing. 

 "Gardening." Song. Instrumental music. Where the sex rSle 

 is reversed. 



CHAPTER XI 

 Reproduction — Nidification . 



The first nest-builder. Origin of nests. Primitive nests. Burrowing. 

 Simple nests. The nests of the Thrush tribe. Complex nests". 

 Pensile nests. Mud nests. The remarkable nests of Tree-swifts." 

 Colonies. Variability in nesting sites. Strange nesting sites! 

 Nest-building and instinct. 



173 



