CHAPTER III. 



THE GLACIAL RANGE CONTRACTION AND POST-GLACIAL 

 EMIGRATION OF BRITISH BIRDS. 



A New Law of Dispersal — The Third Cold Period of the Glacial 

 Epoch — Probable Avifauna of Refuge Area I. during this 

 Period — Effects of Cold Period on the Charadriidse — Inter- 

 polar Migration and Emigration — Avian Characteristics of 

 Refuge Area I. — Avifauna of Refuge Area II. — Resident 

 British Species — Southern Representative Forms — Species 

 Resident in British Isles and in Refuge Area II. — British 

 Species that Resort to Refuge Area II. in Winter — Winter 

 Visitors to the British Isles that also Winter in Refuge Area 

 II. — Summer Visitors to the British Isles — Winter Quarters 

 of these in Refuge Area II. — Ancient Sahara Sea a Bar to 

 Emigration from the South — Birds ranging further South in 

 East Africa than in West Africa — Winter Quarters of British 

 Summer Migrants in Refuge Area III. — Circuitous Routes of 

 Migrants to West Africa — British Summer Migrants from the 

 South-East — British or West European Species that have 

 Emigrated from South-Eastern Areas — Their Absence from 

 Iberia — Their Allied Forms and Representative Species — 

 Influence of Competing Species — Reasons for their Absence 

 from British Area — Abnormal Migrants to British Area — • 

 West European Species normally Absent from British Area — 

 Reasons for such Absence — Past Emigrations of Storks and 

 Red-crested Pochard — Emigrations of Blue-headed Wagtail 

 and Allies — Situation of British Area now unfavourable to 

 Emigration — Instances showing Impassable Nature of a Sea 

 Barrier — Avian Emigration to Greenland — Nearctic Emigra- 

 tion — Post-Glacial Emigration of Birds in West Europe — 

 Emigration to Iceland and Greenland across the British Area 

 — Table of Emigrants. 



Before entering into the details of the subject of this 

 chapter, it may be advisable to promulgate the following 



