CONTEiXTS xiii 



I'AGF, 



Wren — Races of Titmice — Poorness of British Avifauna in 

 Endemic Species— The Channel Islands and Heligoland — 

 West Mediterranean Islands — The Canary Islands — En- 

 demic Birds of — Number of Eggs laid by Birds in Canary 

 Islands — Madeira and the Azores— Japan and the Bonin 

 Isles — Various Tropical Islands — Endemic Avifaunas of — 

 Bearing of Migration on Insular Avifaunas — Conclusions 

 drawn from Facts — Bearing of Glacial Conditions on Island 

 Avifaunas ... ... ... 187 



PART II.— MIGRATION: 



A Study of the Phenomenon of Avian Season-Flight 



ACR0S.S THE BRITISH ARCHIPELAGO. 



CHAPTER VII. 



ROUTES OF .AIIGRATION. 



Difficulty of tracing Routes to British Islands — Definition of 

 a Migration Route — The Gradual Effects of a Changing 

 Climate on Birds — Impulses to Emigration and Migration 

 — The Turnstone and the Rose-coloured Pastor — Ancient 

 Breeding Ranges ■ — Inter-polar and Inter-hemisphere 

 Species — Breeding Grounds and Winter Quarters coales- 

 cing — Routes followed by Summer Migrants to British 

 Area — Routes into the South of England — Species follow- 

 ing them — Routes into Ireland — How followed by Birds 

 — Absence of Routes into Scotland 7nd Ireland ^ — Past 

 Physical Changes indicated by Present Routes of Migra- 

 tion — Persistency shown by Birds in following Migration 

 Routes — Across the English and St. George Channels 

 and the North Sea — Palmen's " Fly Lines "' — The North Sea 

 Routes — Origin of — Effects of Submergence on the Emigra- 

 tion and Migration of Birds — West to East Migration — 

 W^ater Areas a Check to Emigration — Routes followed by 

 Winter Visitors to and Coasting Migrants over the British 

 Islands — The Routes of Migration that are most followed — 

 Inland Continuation of Migration Routes — Difficulty of 

 Tracing — Correlation of Routes with Breeding Grounds ... 209 



