152 THE MIGRATION OF BIRDS. 



{Coturnix communis) is a spring visitor to and breeds 

 in South Africa; and this seems to confirm the 

 view that there is somewhere in Central Africa a 

 Neutral Zone of non-breeding birds of various 

 species, part of which come north to breed in the 

 Palasarctic region, and the other part go south to 

 breed in the temperate portions of the Ethiopian 

 region. As yet there is no evidence whatever to 

 show that the breeding area of the Quail is 

 continuous. The Black-necked Grebe {Podiceps 

 mgricoUis) is another good instance. From what 

 we have already observed, I strongly suspect that 

 this Neutral Zone will eventually be discovered ; 

 it is postulated on this evidence, especially when 

 we bear in mind that there are no localities suitable 

 for the breeding-grounds of decidedly temperate 

 species in equatorial Africa. Brazil and the Malay 

 Archipelago maay also contain such Neutral Zones. 

 These, however, are questions connected with the 

 science of Migration that must be left to future 

 research to solve. I allude to them, because it 

 seems to me they suggest a way to great 

 discoveries. 



There is one other point connected with migration 

 in the Southern Hemisphere which tends to confirm 

 the views previously expressed on this subject, and 

 that is the isolation of many species of birds in the 

 Southern Hemisphere obviously nearly allied to 

 northern types. This is just what we should expect 

 to find upon the Antarctic regions becoming 

 glaciated. Most if not all of these upland species 



